ReShape Lifesciences (RSLS) 10-K27 Feb 202019 FY Annual reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2019	Feb. 18, 2020	Jun. 28, 2019
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Registrant Name	OBALON THERAPEUTICS INC
Entity Central Index Key	0001427570
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		7,731,633
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Public Float			$ 16.6

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 14,055	$ 21,187
Short-term investments	0	2,548
Accounts receivable, net	285	870
Inventory	1,936	1,580
Other current assets	1,959	2,462
Total current assets	18,235	28,647
Lease right-of-use assets	1,077
Property and equipment, net	1,081	1,739
Total assets	20,393	30,386
Current liabilities:
Accounts payable	648	1,159
Accrued compensation	820	3,805
Deferred revenue	424	352
Other current liabilities	1,524	1,985
Current portion of lease liabilities	561
Current portion of long-term loan	0	9,930
Total current liabilities	3,977	17,231
Lease liabilities long-term	567
Other long-term liabilities	0	48
Total liabilities	4,544	17,279
Commitments and contingencies (See Note 10)
Stockholders’ equity:
Common stock, $0.001 par value; 100,000,000 shares authorized at December 31, 2019 and December 31, 2018; 7,724,100 and 2,351,333 shares issued and outstanding at December 31, 2019 and December 31, 2018, respectively	8	2
Additional paid-in capital	188,271	161,859
Accumulated deficit	(172,430)	(148,754)
Total stockholders’ equity	15,849	13,107
Total liabilities and stockholders’ equity	$ 20,393	$ 30,386

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	300,000,000
Common stock, shares issued (in shares)	7,724,100	2,351,333
Common stock, shares outstanding (in shares)	7,724,100	2,351,333

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Revenue	$ 3,281	$ 9,101
Cost of revenue	2,950	5,423
Gross profit	331	3,678
Operating expenses:
Research and development	6,893	10,697
Selling, general and administrative	16,668	29,946
Total operating expenses	23,561	40,643
Loss from operations	(23,230)	(36,965)
Interest expense, net	(385)	(226)
Other expense	(61)	(189)
Net loss	(23,676)	(37,380)
Other comprehensive income	0	5
Net loss and comprehensive loss	$ (23,676)	$ (37,375)
Net loss per share, basic and diluted (in dollars per share)	$ (5.03)	$ (19.64)
Weighted-average common shares outstanding, basic and diluted (in shares)	4,706,775	1,903,734

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive (loss) income	Accumulated deficit
Beginning Balance at Dec. 31, 2017	$ 35,113	$ 2	$ 146,490	$ (5)	$ (111,374)
Beginning Balance (in shares) at Dec. 31, 2017		1,750,061
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	4,693		4,693
Issuance of common stock for cash upon exercise of stock options	53		53
Issuance of common stock for cash upon exercise of stock options (in shares)		4,582
Vesting of early exercised stock options	57		57
Issuance of common stock under ESPP	148		148
Issuance of common stock under ESPP (in shares)		4,526
Issuance of common stock, net of issuance costs	10,418		10,418
Issuance of common stock, net of issuance costs (in shares)		572,269
Issuance of restricted stock awards, net of cancellations		19,895
Issuance of restricted stock awards, net of cancellations (in shares)	0
Unrealized gain (loss) on short term investments	5			5
Net loss	(37,380)				(37,380)
Ending Balance at Dec. 31, 2018	$ 13,107	$ 2	161,859	0	(148,754)
Ending Balance (in shares) at Dec. 31, 2018	2,351,333	2,351,333
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 2,983		2,983
Issuance of common stock for cash upon exercise of stock options	$ 0
Issuance of common stock for cash upon exercise of stock options (in shares)	118	119
Vesting of early exercised stock options	$ 58		58
Issuance of common stock and warrants, net of issuance costs	23,366	$ 4	23,362
Issuance of common stock and warrants, net of issuance costs (in shares)		3,661,238
Unrealized gain (loss) on short term investments	0
Exercise of warrants for the purchase of common stock	2	$ 2
Exercise of warrants for the purchase of common stock (in shares)		1,735,000
Cancellation of restricted stock awards	$ 0
Cancellation of restricted stock awards (in shares)	(26,910)
Issuance of round up common stock for reverse stock split	$ 9		9
Issuance of round up common stock for reverse stock split (in shares)		3,320
Net loss	(23,676)				(23,676)
Ending Balance at Dec. 31, 2019	$ 15,849	$ 8	$ 188,271	$ 0	$ (172,430)
Ending Balance (in shares) at Dec. 31, 2019	7,724,100	7,724,100

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating activities:
Net loss	$ (23,676)	$ (37,380)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	479	581
Stock-based compensation	2,983	4,693
Amortization of right-of-use asset	415	0
Loss on disposal of fixed assets	128	107
Accretion of investment discount, net	(2)	(50)
Amortization of debt discount	70	37
Change in operating assets and liabilities:
Accounts receivable, net	585	3,353
Inventory	12	(162)
Other current assets	411	98
Accounts payable	(543)	70
Accrued compensation	(2,985)	(689)
Deferred revenue	72	(158)
Lease liabilities, net	(364)	0
Other current and long-term liabilities	(451)	68
Net cash used in operating activities	(22,866)	(29,432)
Investing activities:
Purchases of short-term investments	0	(9,102)
Maturities of short-term investments	2,550	29,901
Purchases of property and equipment	(194)	(1,282)
Net cash provided by investing activities	2,356	19,517
Financing activities:
Proceeds from issuance of common stock and warrants, net of issuance costs	23,377	9,823
Proceeds from long-term loan, net of issuance costs	10,000	0
Fees paid in connection with fifth amendment to loan and security agreement	0	(30)
Repayments of long-term loans	(20,000)	0
Proceeds from common stock issued under employee stock purchase plan	0	148
Proceeds from sale of common stock upon exercise of stock options	1	53
Net cash provided by financing activities	13,378	9,994
Net (decrease) increase in cash and cash equivalents	(7,132)	79
Cash and cash equivalents at beginning of period	21,187	21,108
Cash and cash equivalents at end of period	14,055	21,187
Supplemental cash flow information:
Interest paid	719	642
Income taxes paid	0	7
Property and equipment in accounts payable	32	201
Unpaid issuance costs	0	250
Fair value of commitment shares issued	$ 0	$ 595

Organization and Basis of Prese

Organization and Basis of Presentation	12 Months Ended
Organization and Basis of Presentation	Dec. 31, 2019
Accounting Policies [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation The Company Obalon Therapeutics, Inc., or the Company, was incorporated in the state of Delaware on January 2, 2008. The Company is a vertically-integrated medical device company focused on developing and commercializing innovative medical devices to treat obesity. Using its patented technology, the Company has developed the Obalon® balloon system, the first and only U.S. Food and Drug Administration, or FDA, approved swallowable, gas-filled intragastric balloon designed to provide progressive and sustained weight loss in obese patients. Basis of Presentation The consolidated financial statements include the accounts of Obalon Therapeutics, Inc., and its wholly owned subsidiary, Obalon Center for Weight Loss, Inc. The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP, and include the Company's accounts and accounts of its wholly-owned subsidiary. The Company also consolidates variable interest entities (“VIE”) for which it is the primary beneficiary. The primary beneficiary has both (a) the power to direct the activities of the VIE that most significantly affect the entity’s economic performance and (b) either the obligation to absorb losses or the right to receive benefits. Refer to Note 11, “Variable Interest Entity” for further details. All intercompany transactions and balances have been eliminated in consolidation. The Company’s principal operations are located in Carlsbad, California and it operates in one business segment. Reverse Stock Split On July 24, 2019, the Company filed a certificate of amendment to its certificate of incorporation with the Secretary of State of the State of Delaware to effect a one-for-ten reverse split of its issued and outstanding common stock. The accompanying consolidated financial statements and notes thereto give retrospective effect to the reverse stock split for all periods presented. All issued and outstanding common stock, options exercisable for common stock, restricted stock units, performance restricted stock units, and per share amounts contained in the consolidated financial statements have been retrospectively adjusted to reflect this reverse stock split for all periods presented. The number of authorized shares of common stock will not be changed by virtue of the reverse stock split and will remain at 100.0 million shares. Liquidity As of December 31, 2019 , the Company has devoted a substantial portion of its efforts to product development, raising capital, and building infrastructure, and, since January 2017, U.S. commercialization. The Company has incurred operating losses and has experienced negative cash flows from operations since its inception. In July 2012, the Company realized initial revenue from its planned principal operations. The Company recognized total revenue of $3.3 million and $9.1 million for the years ended December 31, 2019 and 2018 , respectively. However, the Company has not yet established an ongoing source of revenues sufficient to cover its operating costs and has funded its activities to date almost exclusively from debt and equity financings. As reflected in the accompanying consolidated financial statements, the Company has a limited operating history and the sales and income potential of the Company’s business are unproven. The Company has not been profitable since inception, and as of December 31, 2019 , its accumulated deficit was $172.4 million . Since inception, the Company has financed its operations primarily through private placements of its preferred stock, the sale of common stock in its IPO and in subsequent public and private placements, and, to a lesser extent, debt financing arrangements. The Company expects to continue to incur net losses for the foreseeable future as it continues to launch Obalon-branded retail centers, and continues research and development efforts. As a result, there is substantial doubt about the Company's ability to continue as a going concern for the twelve months following the issuance date of the consolidated financial statements for the year ended December 31, 2019. The Company may need additional funding to pay expenses relating to its operating activities, including selling, general and administrative expenses and research and development expenses. Adequate funding, if needed, may not be available to the Company on acceptable terms, or at all. The failure to obtain sufficient funds on acceptable terms could have a material adverse effect on the Company’s business, results of operations or financial condition. In August 2019, the Company issued and sold an aggregate of (i) 2,427,500 shares of its common stock (including 412,500 shares of common stock pursuant to the partial exercise of the underwriters’ over-allotment option to purchase 562,500 additional shares), (ii) pre-funded warrants to purchase up to 1,735,000 shares of common stock, (iii) accompanying warrants to purchase up to 3,234,375 shares of common stock (including the exercise in full of the underwriters’ over-allotment option to purchase additional warrants to purchase 421,875 shares of common stock) and (iv) an additional warrant to the underwriters for the purchase 37,500 shares of common stock, for net proceeds from the offering of approximately $14.7 million after deducting underwriting discounts and commissions and offering expenses payable by the Company. As of December 31, 2019, the Company had cash and cash equivalents of $14.1 million . Additionally, during the second quarter of 2019, the Company paid down $15.0 million of the principal balance due under the loan and security agreement with Pacific Western Bank (as successor-in-interest to Square 1 Bank) and during the third quarter of 2019, the Company paid down the remaining $5.0 million of principal balance due under the loan and security agreement with Pacific Western Bank, thereby removing the risks and restrictions of carrying long-term debt. See Note 8 for further detail regarding the equity financing transactions. In an effort to address the Company's liquidity concerns, and pay expenses relating to its operating activities, including selling, general and administrative expenses and research and development expenses, on April 2, 2019, the Company commenced an internal restructuring and notified approximately 49 employees, or approximately 50% of the Company's workforce, that their employment was terminated. This restructuring included the elimination of the Company's field sales force and a transition to more centralized customer support and marketing program strategy. Going forward, rather than focusing on selling to physicians, the Company has focused its commercialization efforts on the establishment and operation of Company-owned or managed Obalon-branded retail treatment centers. See Note 12 for further details regarding the restructuring activities. The Company plans to use proceeds from the August 2019 public offering, equity distribution agreement and the Lincoln Park purchase agreement to the extent needed to fund operations. If the Company is unable to execute against its strategic plan, the Company may be required to delay the development of one or more of their products, delay clinical trials necessary to market their products, or delay establishment or expansion of sales and marketing capabilities. See Note 8 for further detail regarding the 2019 equity financing transactions. Equity Distribution Agreement In December 2018, the Company entered into an equity distribution agreement (the "Equity Distribution Agreement"), with Canaccord Genuity LLC ("Canaccord"), pursuant to which the Company may, from time to time, sell shares of its common stock, par value $0.001 per share (the "ATM Shares"), having an aggregate offering price of up to $10 million through Canaccord, as its sales agent. Lincoln Park Purchase Agreement In February 2020, the Company entered into a new purchase agreement with Lincoln Park Capital Fund, LLC. See Note 13 for further details.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Reported amounts and note disclosures reflect the overall economic conditions that are most likely to occur and anticipated measures management intends to take. Actual results could differ materially from those estimates. All revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods affected. Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents include cash in readily available checking and money market accounts. Fair Value Measurements The carrying values of the Company’s financial instruments, including cash and cash equivalents, accounts receivable, accounts payable, and accrued expenses approximate their fair values due to the short maturity of these instruments. The carrying value of the term loan approximates its fair value as the interest rate and other terms are that which are currently available to the Company. The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels in accordance with authoritative accounting guidance: ▪ Level 1 inputs: Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. ▪ Level 2 inputs: Other than quoted prices included in Level 1 inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability. ▪ Level 3 inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at measurement date. Accounts Receivable Receivables are unsecured and are carried at net realizable value including an allowance for estimated uncollectible amounts. Trade credit is generally extended on a short-term basis; thus trade receivables do not bear interest, although a finance charge may be applied to such receivables that are more than 30 days past due. The allowance for doubtful accounts is based on the Company’s assessment of the collectability of customer accounts. The Company regularly reviews the allowance by considering factors such as historical expense, credit quality, the age of the account receivable balances, and current economic conditions that may affect a customer’s ability to pay. Amounts determined to be uncollectible are charged or written off against the reserve. The Company’s allowance for doubtful accounts was $0.5 million and $0.7 million at December 31, 2019 and 2018, respectively. Concentrations of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash equivalents and trade accounts receivable, which are generally not collateralized. The Company limits its exposure to credit loss by placing its cash equivalents with high credit quality financial institutions and investing in high quality short-term debt instruments. The Company’s customers consist of physicians and institutions in the United States and one international distributor. The Company establishes customer credit policies related to its accounts receivable based on historical collection experiences within the various markets in which the Company operates, historical past-due amounts, and any specific information that the Company becomes aware of such as bankruptcy or liquidity issues of customers. The following table summarizes certain financial data for the customers who accounted for 10.0% or more of sales and accounts receivable. Year ended December 31, Revenue 2019 2018 Customer A 19.7 % 3.4 % Customer B 17.9 % 48.4 % Customer C — % 14.1 % Accounts Receivable December 31, 2019 December 31, 2018 Customer A 20.8 % 2.1 % Customer B — % — % Customer C — % 0.7 % The Company's largest customer for the year ended December 31, 2019 was a U.S. physician, and for the year ended December 31, 2018 the largest customer was its Middle East distributor in Kuwait. Inventory Inventory is stated at the lower of cost (which approximates actual cost on a first-in, first-out basis) or net realizable value, computed on a standard cost basis. Inventory that is obsolete or is in excess of forecasted usage is written down to its estimated net realizable value based on assumptions about future demand. Inventory write-downs are charged to cost of revenue and establish a new cost basis for the inventory. Property and Equipment Property and equipment are stated at cost and depreciated over the estimated useful lives of the assets. Maintenance and repairs are charged to expense as incurred. Assets not yet placed in use are not depreciated. The useful lives of the property and equipment are as follows: Computer hardware 3 years Computer software 3 years Leasehold improvements Shorter of lease term or useful life Furniture and fixtures 5 years Scientific equipment 5 years Impairment of Long-Lived Assets The Company evaluates property and equipment for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparison of the carrying amount of the assets to the future undiscounted net cash flows, which the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured as the difference between the carrying amount and the fair value of the impaired asset. The Company did not recognize any material impairment losses for the respective years ended December 31, 2019 and 2018. Leases Effective January 1, 2019, the Company adopted ASC No. 2016‑02, Leases (Topic 842) (“ASU 2016‑02” or “ASC 842”) , which supersedes the current accounting for leases, using the modified retrospective transition method. The Company has elected to apply the practical expedients allowed by the standard for existing leases. The new standard, while retaining two distinct types of leases, finance and operating, (i) requires lessees to record a right-of-use (“ROU”) asset and a related liability for the rights and obligations associated with a lease, regardless of lease classification, and recognize lease expense in a manner similar to current accounting, (ii) eliminates current real estate specific lease provisions, (iii) modifies the lease classification criteria and (iv) aligns many of the underlying lessor model principles with those in the new revenue standard. The Company determines the initial classification and measurement of its ROU asset and lease liabilities at the lease commencement date and thereafter, if modified. The Company recognizes a ROU asset for its operating leases with lease terms greater than 12 months. The lease term includes any renewal options and termination options that the Company is reasonably assured to exercise. The present value of lease payments is determined by using the incremental borrowing rate for operating leases determined by using the incremental borrowing rate of interest that the Company would pay to borrow on a collateralized basis an amount equal to the lease payments in a similar economic environment and term. The Company applied the new guidance to its existing facility lease at the time of adoption and recognized a ROU asset and lease liability of $1.2 million and $1.3 million , respectively, during the first quarter of 2019. The Company recorded an immaterial amount of lease liabilities, ROU assets, and interest expense associated with finance leases as of and for the year ended December 31, 2019. The current and long-term portions of finance lease liabilities are presented within the current portion of lease liabilities and lease liabilities long-term line items on the consolidated balance sheet, respectively. Finance lease ROU assets are presented within the lease right-of-use assets line item on the consolidated balance sheet. Rent expense for operating leases is recognized on a straight-line basis over the reasonably assured lease term based on the total lease payments and is included in research and development and general and administrative expenses in the statements of operations. Variable Interest Entities The Company evaluates its ownership, contractual and other interests in entities that are not wholly-owned to determine if these entities are VIEs, and, if so, whether the Company is the primary beneficiary of the VIE. In determining whether the Company is the primary beneficiary of a VIE and therefore required to consolidate the VIE, the Company applies a qualitative approach that determines whether the Company has both (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (2) the obligation to absorb losses of, or the rights to receive benefits from, the VIE that could potentially be significant to that VIE. The Company continuously assesses whether it is the primary beneficiary of a VIE, as changes to existing relationships or future transactions may result in the consolidation or deconsolidation of such VIE. Research and Development Costs All research and development costs are charged to expense as incurred. Research and development expenses primarily include (i) payroll and related costs associated with research and development performed, (ii) costs related to clinical and preclinical testing of our technologies under development and (iii) other research and development expenses. Clinical Trial Expenses The Company enters into contracts with third party hospitals and doctors to perform clinical trial activities. The Company accrues expenses for clinical trial activities performed by third parties based on estimates of work performed by each third party as of the balance sheet date. The Company’s clinical trial expense is primarily driven by patient visits to the third party hospitals and doctors. As such, the Company accrues expense for actual patient visits based on third-party reporting and the contractually agreed upon cost for each visit to calculate its clinical accrual. Stock-Based Compensation Stock-based awards issued to employees and directors, are recorded at fair value as of the grant date and recognized as expense on a ratable basis over the employee’s or director’s requisite service period (generally the vesting period). The fair value of incentive stock options is estimated using the Black-Scholes option pricing model. The fair value of restricted stock awards and restricted stock units is estimated using the Company's stock price on the grant date. Because non-cash stock compensation expense is based on awards ultimately expected to vest, it is reduced by an estimate for future forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates. Income Taxes Income taxes are accounted for under the asset-and-liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. Valuation allowances are established, when necessary, to reduce deferred tax assets to the amount expected to be realized. The Company accounts for interest and penalties related to income tax matters, if any, as a component of income tax expense or benefit. Revenue recognition The Company recognizes revenue, in accordance with ASC 606, when control of its products is transferred to its customers in an amount that reflects the consideration it expects to receive in exchange for those products. The Company's revenue recognition process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the transaction price, allocating the transaction price to the distinct performance obligations in the contract, and recognizing revenue as performance obligations are satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. The Company considers a performance obligation satisfied once it has transferred control of a good or service to the customer, meaning the customer has the ability to use and obtain the benefit of the good or service. The Company recognizes revenue for satisfied performance obligations only when it determines there are no uncertainties regarding payment terms or transfer of control. Revenue is primarily generated from sales of the Obalon Balloon System to physicians and institutions in the United States, patients treated at the Obalon branded retail center, and sales to distributors in the Middle East. In sales to these customers, the Company recognizes revenue upon shipment of its product as the Company's standard contract terms dictate that control transfers to the customer upon shipment of its product. Invoicing typically occurs upon shipment and the time period between invoicing and when payment is due is not significant. Sales taxes collected are excluded from revenues. Shipping charges billed to customers are included in revenue and related shipping cost is included in cost of revenue. The Company's revenue contracts do not provide for maintenance. Revenue generated from the treatment centers that began treating patients in October 2019 is recognized as the distinct service performance obligations are delivered to customers. Commissions are considered incremental costs to obtain a contract with a customer and paid to salespeople when contracts are executed. Commissions from both private practice and treatment center revenues are recognized as a selling expense when incurred as the amortization period is one year or less. The components of the Obalon Balloon System, in sales to physicians and Middle East distributors, are typically packaged in a kit and shipped to the customer at the same time, satisfying the majority of performance obligations in the contract. Revenues from the treatment center are recognized as the Company delivers the distinct performance obligations. The Company records deferred revenue at the treatment center whenever the Company receives cash payments prior to the fulfillment of the distinct performance obligations. The Company recognizes revenue for any unsatisfied, distinct performance obligations, such as undelivered components, as they are satisfied based on the estimated standalone selling price of each performance obligation. The Company estimates the standalone selling price of each performance obligation by estimating the expected cost of satisfying that performance obligation plus an appropriate margin and also third-party evidence for certain performance obligations from treatment center revenues. When the Company enters into contracts with multiple performance obligations, such obligations are generally satisfied within a short time frame of approximately three to six months after the contract execution date. The Company does not disclose the value of the unsatisfied performance obligations within its contracts. The Company offers a swallow guarantee program in the United States where it may provide replacement balloons to customers when their patients are unsuccessful in swallowing an Obalon balloon, subject to certain requirements and restrictions. The Company considers the replacement balloons provided under this program as an additional performance obligation in the contract and defers revenue relating to the replacement balloons based on an expected swallow failure rate and then recognizes revenue when replacement balloons are provided. The Company recognizes revenue at the net sales price, which reflects the consideration the Company believes it is most likely to receive. The net sales price includes estimates of variable consideration for customer incentives and returns. The Company reserves for product returns as a reduction to revenue in the period when the related revenue is recognized. The Company estimates its product returns based on historical return rates and specifically known events. Estimated costs of customer incentive programs are recorded at the time the incentives are offered, based on the specific terms and conditions of the program. Customer incentives that provide discounts to the customer on purchases of current or future product are recorded as a reduction of revenue in the period the related product revenue is recognized. Any consideration payable to a customer is presumed as a reduction to revenue unless the Company can demonstrate that the consideration provided to the customer is in exchange for a distinct good or service. Actual amounts of consideration ultimately received may differ from the Company’s estimates. If actual results vary from the Company’s estimates, the Company would adjust these estimates, which would impact net product revenue and results of operations in the period such variances become known. Product Warranty The Company warranties its products to be of good quality and free from defects in design, materials, or workmanship for approximately one year from the date of purchase. The Company accrues for the estimated future costs of repair or replacement upon shipment. The warranty accrual is recorded to cost of revenue and is based on historical and forecasted trends in the volume of product failures during the warranty period and the cost to repair or replace the equipment. It is possible that the Company’s underlying assumptions will not reflect the actual experience and in that case, future adjustments will be made to the recorded warranty obligation. The warranty expense as of December 31, 2019 and 2018 was immaterial. Advertising Costs Advertising costs are expensed as incurred and included in selling, general and administrative expense. Advertising costs for the years ended December 31, 2019 and 2018 were approximately $0.8 million and $3.8 million , respectively. Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period without consideration for common stock equivalents. Diluted net loss per share is the same as basic net loss per common share, since the effects of potentially dilutive securities are anti-dilutive due to the net loss position of all periods presented. Potentially dilutive common stock equivalents are comprised of warrants, unvested restricted stock awards (RSAs), and unexercised stock options outstanding under the Company's equity plan. Recently Issued and Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, or FASB, or other standard setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption. Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). Under this new guidance, at the commencement date, lessees will be required to recognize (i) a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis and (ii) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. This guidance is not applicable for leases with a term of 12 months or less. In July 2018, the FASB issued ASU 2018-10, Codification Improvements to Topic 842 (Leases), which provides narrow amendments to clarify how to apply certain aspects of the new lease standard. The new standard is effective for annual reporting periods, and interim periods within those periods, beginning after December 15, 2018, with early adoption permitted. In July 2018, the FASB issued ASU No. 2018-11, Leases Topic (842): Targeted Improvements. This ASU provides companies an option to apply the transition provisions of the new lease standard at its adoption date instead of at the earliest comparative period presented in its financial statements. The Company elected the optional method to account for the impact of the adoption with a cumulative-effect adjustment in the period of adoption, if needed, and did not restate prior periods. The Company elected certain practical expedients permitted under the transition guidance. As part of the adoption, the Company recorded a ROU asset and liability upon adoption of the guidance pertaining to its long-term real estate lease for its corporate facilities. No cumulative-effect adjustment was needed. In February 2018, the FASB issued Accounting Standards Update ("ASU") 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220). The new guidance permits, but does not require, companies to reclassify the stranded tax effects of the Tax Cuts and Jobs Act on items within accumulated other comprehensive income to retained earnings. The Company adopted this standard in the first quarter of 2019, which did not have a material impact on its consolidated financial statements. Recently Issued Accounting Pronouncements not yet adopted In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13, Financial Instruments - Credit Losses, which changes the accounting for recognizing impairments of financial assets. Under the new guidance, credit losses for certain types of financial instruments will be estimated based on expected losses. The new guidance also modifies the impairment models for available-for-sale debt securities and for purchased financial assets with credit deterioration since their origination. In February 2020, the FASB issued ASU 2020-02, Financial Instruments-Credit Losses (Topic 326) and Leases (Topic 842) - Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 119 and Update to SEC Section on Effective Date Related to Accounting Standards Update No. 2016-02, Leases (Topic 842) , which amends the effective date of the original pronouncement for smaller reporting companies. ASU 2016-13 and its amendments will be effective for the Company for interim and annual periods in fiscal years beginning after December 15, 2022. The Company believes the adoption will modify the way the Company analyzes financial instruments, but it does not anticipate a material impact on results of operations. The Company is in the process of determining the effects the adoption will have on its consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820); Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. This guidance removes certain disclosure requirements related to the fair value hierarchy, modifies existing disclosure requirements related to measurement uncertainty and adds new disclosure requirements. The new disclosure requirements include disclosing the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and the range and weighted-average of significant unobservable inputs used to develop Level 3 fair value measurements. Certain disclosures required by this guidance must be applied on a retrospective basis and others on a prospective basis. The guidance will be effective for fiscal years beginning after December 15, 2019, although early adoption is permitted. The Company is currently evaluating this guidance to determine the impact, if any, it may have on its consolidated financial statements.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Instruments Recorded at Fair Value on a Recurring Basis The Company has segregated all financial assets and liabilities that are measured at fair value on a recurring basis (at least annually) into the most appropriate level within the fair value hierarchy based on the inputs used to determine the fair value at the measurement date in the table below. Assets and liabilities measured at fair value on a recurring basis at December 31, 2019 and 2018 are as follows (in thousands): Fair value measurements at reporting date using Balance as of December 31, 2019 Quoted prices Significant Significant Assets: Cash $ 1,012 $ 1,012 Cash Equivalents: Money Market Funds 13,043 13,043 — — Total assets $ 14,055 $ 14,055 $ — $ — Fair value measurements at reporting date using Balance as of December 31, 2018 Quoted prices in active Significant (Level 2) Significant (Level 3) Assets: Cash $ 18,384 $ 18,384 Cash Equivalents: Money Market Funds 2,803 2,803 — — Short-term investments: U.S. Treasury bonds 2,548 2,548 — — Total assets $ 23,735 $ 23,735 $ — $ — The Company’s investments in Level 1 assets are valued based on publicly available quoted market prices for identical securities as of December 31, 2019 and 2018 . Instruments Not Recorded at Fair Value on a Recurring Basis The estimated fair value of the Company's long-term loan as of December 31, 2018 is determined by Level 2 inputs and is based primarily on quoted market prices for the same or similar issues. The recorded value of the Company's long-term loan approximates the current fair value as the interest rate and other terms are that which are currently available to the Company.

Net Loss per Share

Net Loss per Share	12 Months Ended
Net Loss per Share	Dec. 31, 2019
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share The following table sets forth the computation of basic and diluted net loss per share of common stock (in thousands, except shares and per share data): Year ended December 31, 2019 2018 Net loss $ (23,676 ) $ (37,380 ) Weighted-average common shares outstanding, basic and diluted 4,706,775 1,903,734 Net loss per share, basic and diluted $ (5.03 ) $ (19.64 ) The following table sets forth the outstanding potentially dilutive securities determined using the treasury stock method that have been excluded in the calculation of diluted net loss per share because to do so would be anti-dilutive (in common stock equivalent shares): Year ended December 31, 2019 2018 Stock options to purchase common stock 8,900 38,352 Total 8,900 38,352

Balance Sheet Details

Balance Sheet Details	12 Months Ended
Balance Sheet Details	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Details	Balance Sheet Details Inventory consists of the following (in thousands): December 31, 2019 2018 Raw materials $ 1,835 $ 1,090 Work in process 12 288 Finished goods 89 202 Total $ 1,936 $ 1,580 Other current assets consist of the following (in thousands): December 31, 2019 2018 Prepaid expenses $ 1,890 $ 2,329 Interest receivable 0 12 Other assets 69 121 Total $ 1,959 $ 2,462 Property and equipment, net consist of the following (in thousands): December 31, 2019 2018 Computer hardware $ 263 $ 410 Computer software 291 274 Leasehold improvements 497 405 Furniture and fixtures 247 178 Scientific equipment 1,999 1,921 Construction in progress, or CIP 110 530 3,407 3,718 Less: accumulated depreciation (2,326 ) (1,979 ) Total $ 1,081 $ 1,739 Depreciation expense for the years ended December 31, 2019 and 2018 was $ 0.5 million and $0.6 million for each period, respectively. Other current liabilities consist of the following (in thousands): December 31, 2019 2018 Accrued legal and professional fees $ 412 $ 624 Accrued customer incentives 198 467 Accrued sales and other taxes 107 132 Returns reserve liability 315 214 Other accrued expenses 492 548 Total $ 1,524 $ 1,985

Term Loan

Term Loan	12 Months Ended
Term Loan	Dec. 31, 2019
Debt Disclosure [Abstract]
Term Loan	Term Loan In June 2013, the Company entered into a $3.0 million loan and security agreement (the "Loan Agreement") with Square 1 Bank (predecessor-in-interest to Pacific Western Bank), which it subsequently amended in October 2014, September 2016, December 2016, June 2017 and July 2018. In July 2018, the Company executed the Fifth Amendment to the Loan and Security Agreement (the "Loan Amendment") with Pacific Western Bank, which increased the loan capacity to $20 million from $10 million . The loan capacity of $20 million consists of two tranches as follows: a first tranche consisting of $10.0 million funded on July 10, 2018, of which the full $10.0 million was required to settle the existing debt with Pacific Western Bank on a net settlement basis (pursuant to its original terms); and a second tranche consisting of an additional $10.0 million which may be drawn at any time prior to July 9, 2019. During the first quarter of 2019, the Company drew down on the remaining $10.0 million tranche. During the second quarter of 2019, the Company paid down $15.0 million of the principal balance due under the Loan Agreement. During the third quarter of 2019, the Company paid down the remaining $5.0 million of principal balance due under the term loan, thereby removing the risks and restrictions of carrying long-term debt. As of December 31, 2019, the Company had no outstanding borrowings under the Loan Agreement. The debt that was repaid in the third quarter of 2019 had a variable annual interest rate equal to the greater of the prime rate plus 1.5% per annum, or 5% , and would have matured in July 2022. While the debt was outstanding in 2019, the prime rate was 5.5% , resulting in an interest rate on the debt of 7.0% at the time that the Company paid down the remaining debt. The Loan Amendment provided for an interest-only period through July 9, 2019 followed by 36 equal monthly installments of principal and interest with the first principal payment due on August 9, 2019. Under the terms of the Loan Agreement, the Company could prepay the debt in full at any time with no additional cost, which occurred in August 2019. Upon repayment of the outstanding debt in full, the Loan Agreement was terminated and the Company is no longer subject to the covenants and restrictions set forth in the Loan Agreement. The loan fee paid and the remaining balance of debt issuance costs and debt discount on the previous loan agreement held with Pacific Western Bank were amortized to interest expense during the third quarter of 2019. As of December 31, 2019, there were no unamortized debt issuance costs due to the $15.0 million and $5.0 million payments on the Company's term loan in the second and third quarters of 2019, respectively.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
Stock-Based Compensation	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Equity Incentive Plans On October 4, 2016, the 2016 Equity Incentive Plan, or the 2016 Plan, became effective. The 2016 Plan serves as a successor to the 2008 Plan. The 2016 Plan permits the award of stock options, restricted stock awards, stock appreciation rights, restricted stock units, performance awards, cash awards and stock bonuses. The Company reserved 223,673 shares of common stock for issuance as of January 1, 2019 under the 2016 Plan. The number of shares reserved for issuance under the 2016 Plan increases automatically on January 1 of each calendar year continuing through the tenth calendar year during the term of the 2016 Plan by the number of shares equal to 4% of the total outstanding shares of the Company's common stock and common stock equivalents as of the immediately preceding December 31. At December 31, 2019, 5,337 shares remained available for future grant under the 2016 Plan. The Company determines the fair value of each stock option or award on the grant date and recognizes that fair value as stock-based compensation straight-line over the vesting term of the award. The Company estimates forfeitures at the time of grant based on historical data and records stock-based compensation only for options and awards expected to vest. The Company revises its forfeiture estimates on an at least annual basis and records any difference as a cumulative adjustment in the period the estimates are revised. The Company recorded total non-cash compensation, including non-cash compensation to employees and nonemployees in the consolidated statements of operations and comprehensive loss as follows (in thousands): Year ended December 31, 2019 2018 Cost of revenue $ (21 ) $ 96 Research and development 739 1,141 Selling, general and administrative 2,265 3,456 Total $ 2,983 $ 4,693 Unrecognized stock-based compensation expense at December 31, 2019 for all stock-based compensation pertaining to options was approximately $1.7 million . Expense associated with all stock-based compensation is expected to be recognized over a weighted-average term of 2.4 years . Incentive Stock Options Recipients of incentive stock options can purchase shares of the Company’s common stock at a price equal to the stock's fair market value on the grant date, based on the closing price of the Company's stock on the grant date. Options granted generally expire after 10 years. Options granted generally vest 25% on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining three years , subject to continued employment. The fair value of each option granted was estimated on the date of grant using the Black-Scholes option pricing model using the following assumptions: Year ended December 31, 2019 2018 Assumed risk-free interest rate (1) 1.67% - 2.58% 2.31% - 3.10% Assumed volatility (2) 55.07% - 65.21% 53.95% - 55.44% Expected option life (3) 6.1 years 5.0 - 6.1 years Expected dividend yield (4) —% —% (1) The risk-free interest rate was determined based on the U.S. Treasury yield in effect at the time of the grant for zero-coupon U.S. Treasury notes with remaining terms similar to the expected term of the options. (2) The volatility was determined based on analysis of the volatility of a peer group of publicly traded companies as the Company's stock has not traded publicly for a significant time and the Company has limited company specific historical volatility. The peer group was determined considering factors such as stage of development, risk profile, enterprise value and position within the industry. (3) The expected option life was determined using the “simplified method” for estimating the expected option life, which is the average of the weighted-average vesting period and contractual term of the option. (4) The expected dividend yield was zero as the Company has not historically issued dividends and does not expect to do so in the foreseeable future. The following table summarizes stock option transactions for the 2016 Plan for the year ended December 31, 2019 (in thousands, except shares and per share data): Number of Weighted- Weighted- (in years) Aggregate Outstanding at December 31, 2018 336,008 $ 58.29 Options granted 237,197 12.13 Options exercised (118 ) 8.72 Options canceled (54,619 ) 44.46 Outstanding at December 31, 2019 518,468 38.64 6.8 $ 12 Vested and expected to vest at December 31, 2019 475,431 $ 40.60 6.6 $ 9 Vested and exercisable at December 31, 2019 270,613 $ 52.72 6.1 $ 0.3 The weighted-average fair value of options granted during the year ended December 31, 2019 was $6.81 . The intrinsic value of options exercised for the years ended December 31, 2019 and 2018 was immaterial and $0.1 million , respectively. All options outstanding under the previous 2008 Stock Plan, or the 2008 Plan are exercisable under the early exercise provisions of the 2008 Plan. Options granted under the 2008 Plan that are exercised prior to vesting are subject to repurchase by the Company at the original issue price and will vest according to the respective option agreement. There were no options early exercised for the years ended December 31, 2019 and 2018. For prior early exercised options, 1,383 shares remain unvested with an immaterial related liability recorded under other current liabilities on the Company’s consolidated balance sheet as of December 31, 2019 . Restricted Stock Awards The following table summarizes restricted stock award transactions for the year ended December 31, 2019 : Number of awards Weighted- average grant date fair value Outstanding at December 31, 2018 61,198 $ 58.85 Awards granted — — Awards released (4,750 ) 71.50 Awards canceled (26,924 ) 77.70 Outstanding at December 31, 2019 29,524 $ 39.64 The Company's current restricted stock awards vest 100% at various terms from the grant date, subject to continued employment. The fair-value of each restricted stock award is determined on the grant date using the closing price of the Company's common stock on the grant date. Unamortized expense of $0.1 million is expected to be recognized over a weighted-average period of 1.5 years . Restricted Stock Units The following table summarizes restricted stock unit transactions for the 2016 Plan for the year ended December 31, 2019: Number of shares Weighted-average grant date fair value Aggregate intrinsic value (in thousands) Outstanding at December 31, 2018 — $ — Awards granted 55,574 11.70 Awards released — — Awards canceled — — Outstanding at December 31, 2019 55,574 $ 11.70 $ 106 Vested and expected to vest at December 31, 2019 51,894 $ 11.84 $ 99 The Company's current restricted stock units vest 100% at various terms from the grant date, subject to continued service. The fair-value of each restricted stock unit is determined on the grant date using the closing price of the Company's common stock on the grant date. Unamortized expense of $0.2 million is expected to be recognized over a weighted-average period of 0.6 years . Employee Stock Purchase Plan On October 5, 2016, the 2016 Employee Stock Purchase Plan, or ESPP, became effective. The 2016 ESPP was adopted in order to enable eligible employees to purchase shares of the Company’s common stock at a discount. Purchases will be accomplished through participation in discrete offering periods. The Company reserved 74,520 shares of common stock for issuance under the 2016 ESPP. The number of shares reserved for issuance under the 2016 ESPP increases automatically on January 1 of each calendar year beginning after the first offering date and continuing through the first ten calendar years by the number of shares equal to 1% of the total outstanding shares of our common stock and common stock equivalents as of the immediately preceding December 31. The ESPP was suspended in 2019. There were no shares of common stock issued during the year ended December 31, 2019, and 4,526 shares of common stock issued during the year ended December 31, 2018 pursuant to the ESPP.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2019
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity In June 2018, the Company amended its certificate of incorporation to reduce the authorized number of shares of common stock from 300,000,000 to 100,000,000 . Public Offering and related warrants On August 1, 2019, the Company entered into an underwriting agreement with A.G.P./Alliance Global Partners, as underwriter, in connection with a public offering of the Company's securities, pursuant to which the Company issued and sold (i) 2,427,500 shares of common stock (including 412,500 shares of common stock pursuant to the partial exercise of the underwriters’ over-allotment option to purchase 562,500 additional shares), (ii) pre-funded warrants to purchase up to 1,735,000 shares of common stock (“Pre-funded Warrants”), (iii) accompanying warrants to purchase up to 3,234,375 shares of common stock (including the exercise in full of the underwriters’ over-allotment option to purchase additional warrants to purchase 421,875 shares of common stock) (“Purchase Warrants”) and (iv) an additional warrant to the underwriters for the purchase 37,500 shares of common stock (“Representative Warrant”). The offering was made pursuant to a registration statement on Form S-1. The offering closed on August 6, 2019 resulting in gross proceeds of approximately $15.4 million . The Company incurred $0.7 million of legal, accounting, and other fees related to the offering. The shares of common stock and accompanying Purchase Warrants were sold at a public offering price of $4.00 per share, the Pre-funded Warrants and accompanying Purchase Warrants were sold at a public offering of $3.999 . The Purchase Warrants were immediately exercisable upon issuance, will expire on August 6, 2024 and have an exercise price of $4.40 and the Representative Warrant has an exercise price of $5.00 , in each case subject to adjustment in the event of stock dividends, stock splits, stock combinations, reclassifications, reorganizations or similar events. The Representative Warrant is exercisable in February 2020 and expires on August 6, 2024. All of the Pre-funded warrants were exercised during the third quarter of 2019. None of the Purchase or Representative Warrants have been exercised as of December 31, 2019. All of the warrants are recorded within equity in accordance with authoritative accounting guidance. Participation in Follow-on Offering Certain of the Company’s directors, senior management and stockholders, including entities affiliated with holders of 5% or more of our capital stock and certain of our directors, purchased an aggregate of 670,312 shares of our common stock and warrants to purchase shares of our common stock in our follow-on offering of common stock and warrants to purchase shares of our common stock in August 2019 at the same price and on the same terms as the other purchasers in the offering and not pursuant to any pre-existing contractual rights or obligations. Securities Purchase Agreement On May 23, 2019, the Company entered into a Securities Purchase Agreement with certain investors for the sale by the Company of 500,000 shares of the Company's common stock, par value $0.001 per share, at a purchase price of $6.00 per share. The closing of the sale of the shares under the Securities Purchase Agreement occurred on May 28, 2019. The Company incurred $0.4 million of legal, accounting and other professional fees related to the Securities Purchase Agreement. The aggregate gross proceeds for the sale of the shares was $3.0 million . Equity Distribution Agreement On December 27, 2018, the Company entered into the Equity Distribution Agreement (the "Equity Distribution Agreement") with Canaccord Genuity LLC ("Canaccord"), pursuant to which the Company may, from time to time, sell shares of its common stock, having an aggregate offering price of up to $10.0 million through Canaccord, as the Company's sales agent. The Company pays Canaccord a commission of 3.0% of the gross proceeds from the sales of common stock sold pursuant to the terms of the Equity Distribution Agreement. The Equity Distribution Agreement also contains, among other things, customary representations, warranties and covenants by the Company and indemnification obligations of the Company and Canaccord as well as certain termination rights for both the Company and Canaccord. The Company has no obligation to sell any at-the-market ("ATM") shares under the Equity Distribution Agreement, and may at any time suspend solicitation and offers under the Equity Distribution Agreement. Until the aggregate market value of the Company's common stock held by non-affiliates, or public float, is greater than $75.0 million , the amount the Company can raise through primary public offerings of securities in any twelve-month period using shelf registration statements, including sales under the Company's ATM program, is limited to an aggregate of one-third of its public float. The Company incurred $0.2 million of legal, accounting and other professional fees related to the Equity Distribution Agreement. These amounts are included as deferred charges within other current assets on the Company's condensed consolidated balance sheet as of December 31, 2019 and all were charged against paid-in capital upon receipt of proceeds from the sale of common stock under the Equity Distribution Agreement. As of December 31, 2019, the Company has sold 377,615 shares under the Equity Distribution Agreement for aggregate gross proceeds of $2.8 million . Lincoln Park Purchase Agreement On December 27, 2018, the Company entered into a purchase agreement (the "Lincoln Park Purchase Agreement") with the Lincoln Park Capital Fund, LLC ("Lincoln Park") and a registration rights agreement, or the Registration Rights Agreement, with Lincoln Park, pursuant to which the Company has the right, but not the obligation, to sell to Lincoln Park, and Lincoln Park is obligated to purchase up to $20.0 million of the Company's common stock, over the 36 -month period that commenced in February 2019. Under the Lincoln Park Purchase Agreement, and excluding the impact of any adjustments resulting form the Company's reverse stock split, on any business day selected by the Company on which the closing price of its common stock is not less than $0.50 per share (subject to standard anti-dilution adjustments), the Company may direct Lincoln Park to purchase up to 50,000 shares of common stock on such business day (each, a “Regular Purchase”), provided, however, that (i) the Regular Purchase may be increased to up to 100,000 shares, provided that the closing sale price of the common stock is not below $2.00 on the purchase date (subject to standard anti-dilution adjustments) (ii) the Regular Purchase may be increased to up to 125,000 shares, provided that the closing sale price of the common stock is not below $3.00 on the purchase date (subject to standard anti-dilution adjustments) and (iii) the Regular Purchase may be increased to up to 150,000 shares, provided that the closing sale price of the common stock is not below $4.00 on the purchase date (subject to standard anti-dilution adjustments). In each case, Lincoln Park’s maximum commitment in any single Regular Purchase may not exceed $1,000,000 . The purchase price per share for each such Regular Purchase will be based off of prevailing market prices of the Company's common stock immediately preceding the time of sale without any fixed discount. In addition to Regular Purchases, the Company may also direct Lincoln Park to purchase other amounts as accelerated purchases or as additional accelerated purchases if the closing sale price of the common stock exceeds certain threshold prices as set forth in the Lincoln Park Purchase Agreement. Depending on the prevailing market price of our common stock, the Company may not be able to sell shares to Lincoln Park for the maximum $20.0 million over the term of the Lincoln Park Purchase Agreement. For example, under the rules of the Nasdaq Capital Market, in no event may the Company issue more than 19.99% of its shares outstanding (which is approximately 465,470 shares based on 2,328,512 shares outstanding prior to the signing of the Lincoln Park Purchase Agreement) under the Lincoln Park Purchase Agreement unless the Company obtains stockholder approval or an exception pursuant to the rules of the Nasdaq Capital Market is obtained to issue more than 19.99% . This limitation will not apply if, at any time the exchange cap is reached and at all times thereafter, the average price paid for all shares issued and sold under the Lincoln Park Purchase Agreement is equal to or greater than the specified minimum amount set forth in the Lincoln Park Purchase Agreement. The Company is not required or permitted to issue any shares of common stock under the Purchase Agreement if such issuance would breach the its obligations under the rules or regulations of the Nasdaq Capital Market. In addition, Lincoln Park will not be required to purchase any shares of the Company's common stock if such sale would result in Lincoln Park’s beneficial ownership exceeding 9.99% of the then outstanding shares of the Company's common stock. The Company's inability to access a portion or the full amount available under the Lincoln Park Purchase Agreement, in the absence of any other financing sources, could have a material adverse effect on its business. The Company incurred $0.8 million of commitment shares issued, legal, accounting, registration and other professional fees related to the Lincoln Park Purchase Agreement. These amounts are included as deferred charges within other current assets on the Company's balance sheet as of December 31, 2019 and all were charged against paid-in capital upon receipt of proceeds from the sale of common stock under the Lincoln Park Purchase Agreement. As of December 31, 2019, the Company has sold 356,122 shares under the Lincoln Park Purchase Agreement for aggregate gross proceeds of $4.2 million . No future issuances will occur under this agreement. In February 2020, the Company entered into a new purchase agreement and registration rights agreement with Lincoln Park, pursuant to which Lincoln Park has committed to purchase up to $15.0 million of the Company's common stock. In connection with entering into the new purchase agreement, the Company and Lincoln Park terminated the prior purchase agreement. Please see Note 13 for further details. Common Stock Reserved for Future Issuance Common stock reserved for future issuance consists of the following at December 31, 2019 : Stock options issued and outstanding 518,468 Restricted stock units issued and outstanding 55,574 Warrants for the purchase of common stock 3,271,875 Authorized for future option and ongoing vesting of award grants 5,337 Authorized for future issuance under ESPP 74,520 Total 3,925,774

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The income tax provision consists of the following (in thousands): Year ended December 31, 2019 2018 Current: Federal $ — $ — State 14 11 Total current provision 14 11 Deferred: Federal — — State — — Total deferred provision — — Income tax provision $ 14 $ 11 The difference between income tax benefits and income taxes computed using the U.S. federal income tax rate as of December 31, 2019 and 2018 are as follows (in thousands): Year ended December 31, 2019 2018 Federal provision (benefit) At statutory rates $ (4,971 ) $ (7,848 ) Change in valuation allowance 4,985 7,859 Income tax provision $ 14 $ 11 Significant components of the Company’s deferred tax assets and liabilities are as shown below (in thousands): Year ended December 31, 2019 2018 Deferred tax assets: Net operating losses $ 35,252 $ 28,708 Tax credits 5,493 4,898 Capitalized research and development costs 2,401 2,566 Other 2,724 2,458 Total gross deferred tax assets 45,870 38,630 Less valuation allowance (45,578 ) (38,630 ) Total deferred tax assets $ 292 $ — Deferred tax liabilities: Other $ (292 ) $ — Total deferred tax liabilities $ (292 ) $ — A valuation allowance of $ 45.6 million and $ 38.6 million as of December 31, 2019 and 2018, respectively, has been established to offset the deferred tax assets as realization of such assets are uncertain. At December 31, 2019 , the Company had federal and state net operating loss carryforwards of approximately $ 147.9 million and $ 114.6 million , respectively. The federal and state tax loss carryforwards will begin expiring in 2028, unless previously utilized. The federal net operating loss carryover includes $59.7 million of net operating losses generated after 2017. Federal net operating losses generated in 2018 and beyond carryover indefinitely and may generally be used to offset up to 80% of future taxable income. The Company also has federal and California research and development tax credit carryforwards totaling $ 3.4 million and $ 2.7 million , respectively. The federal research and development tax credit carryforward will begin to expire in 2028 unless previously utilized. The California research tax credits do not expire. The Company conducts research and experimentation activities, generating research tax credits for federal and state purposes under IRC Section 41. The Company has not performed a formal study validating these credits claimed in the tax returns. Once a study is prepared, the amount of R&D tax credits available could vary from what was originally claimed on the tax returns. Pursuant to Internal Revenue Code, or IRC, Sections 382 and 383, annual use of the Company’s net operating loss and research and development credit carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period. The Company has not completed an IRC Section 382 and 383 analysis regarding the limitation of net operating loss and research and development credit carryforwards. Due to the existence of the valuation allowance, future changes in the Company's unrecognized tax benefits will not impact its effective tax rate. Any carryforwards that will expire prior to utilization as a result of such limitations will be removed from deferred tax assets with a corresponding reduction of the valuation allowance. In accordance with authoritative guidance, the impact of an uncertain income tax position on the income tax return must be recognized at the largest amount that is more-likely-than-not to be sustained upon an audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. As of December 31, 2019 and 2018, the Company had unrecognized tax benefits of $4.3 million and $3.6 million , respectively. There are no unrecognized tax benefits included on the consolidated balance sheet that would, if recognized, impact the effective tax rate, given the valuation allowance recorded against the deferred tax assets. The Company does not anticipate there will be a significant change in unrecognized tax benefits within the next 12 months. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): Year ended December 31, 2019 2018 Balance at January 1 $ 3,609 $ 2,128 Additions based on tax positions related to current year 643 1,513 Additions based on tax positions related to prior years — — Reductions for tax positions related to prior years (2 ) (32 ) Balance at December 31 $ 4,250 $ 3,609 The Company is subject to taxation in the United States and various state jurisdictions. Due to the net operating loss carryforwards, the U.S. federal and state returns are open to examination for all years since inception. The Company has not been, nor is it currently, under examination by the federal or any state tax authority.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases The Company leases its facilities and retail treatment center under noncancelable operating leases which expire on various dates between 2021 and 2022. In July 2019, the Company entered into an office lease agreement to launch an Obalon-branded retail treatment center in San Diego, California, which expires on August 5, 2021. Under the terms of the facilities and retail center leases, the Company is required to pay its proportionate share of property taxes, insurance and normal maintenance costs. Upon the Company’s adoption of ASC 842 as of January 1, 2019, the Company recognized a ROU asset and lease liability for its building lease, assuming a 7.0% discount rate. Any short-term leases defined as 12 months or less or month-to-month leases were excluded and continue to be expensed each month. Total costs associated with short-term leases for the year ended December 31, 2019 were immaterial. The Company determines if an arrangement is a lease at inception. The exercise of lease renewal options is at the Company’s sole discretion and were not included in the calculation of the Company’s lease liability as the Company is not able to determine without uncertainty if the renewal option will be exercised. The depreciable life of assets and leasehold improvements are limited to the expected term, unless there is a transfer of title or purchase option reasonably certain of exercise. The Company’s lease agreements do not contain any variable lease payments, residual value guarantees or any restrictive covenants. The Company’s ROU assets represent the right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date of the lease or the ASC 842 adoption date, whichever is later, based on the present value of lease payments over the lease term. When readily determinable, the Company uses the implicit rate in determining the present value of lease payments, or 7.0% , as of the adoption date. When leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at the lease commencement date or adoption date, including the lease term. The operating lease ROU asset also includes any lease payments made and excludes lease incentives. Lease expense for lease payments is recognized on a straight-line basis over the lease term. Future minimum annual lease payments under such leases were as follows as of December 31, 2019 (in thousands): Operating leases: 2020 $ 537 2021 517 2022 117 Total undiscounted lease payments - operating leases $ 1,171 Finance leases: 2020 $ 24 2021 24 Total undiscounted lease payments - finance leases $ 48 Total undiscounted lease payments $ 1,219 Less: imputed interest $ (91 ) Lease liability $ 1,128 Less: current portion of lease liability $ (561 ) Lease liability, less current portion $ 567 As of December 31, 2019, the Company’s remaining lease terms range from 1.6 to 2.3 years . Rent expense totaled and $0.6 million and $0.4 million for the year ended December 31, 2019 and 2018, respectively. The Company paid $0.5 million of cash payments related to its operating lease agreement for the year ended December 31, 2019. Supplier Contracts The Company enters into contracts in the normal course of business with clinical trial sites and clinical supply manufacturing organizations and with vendors for preclinical studies, research supplies and other services and products for operating purposes. These contracts generally provide for termination after a notice period, and, therefore, are cancelable contracts. Pursuant to the Company's supplier agreement entered into in December 2018, the Company is obligated to purchase certain minimum quantities. These costs scale up as the Company's projected manufacturing volume increases. Under the terms of the agreement, the Company can reduce the forecasted minimum quantities and is required to incur a holding fee for items manufactured by the supplier. This represents the one year minimum commitment of approximately $0.5 million as of December 31, 2019. Termination of Stock Offering On January 23, 2018, the Company issued a press release announcing the termination of its previously announced offering of common stock due to a purported whistleblower compliant, which was later found to be without merit. As of December 31, 2019, the Company did not record any liability associated with termination of the offering, and management believed that the likelihood is remote that the Company will incur material fees in the future. Shareholder Lawsuit On February 14 and 22, 2018, plaintiff stockholders filed class action lawsuits against us and certain of our executive officers in the United States District Court for the Southern District of California (Hustig v. Obalon Therapeutics, Inc., et al., Case No. 3:18-cv-00352-AJB-WVG, and Cook v. Obalon Therapeutics, Inc. et al., Case No. 3:18-cv-00407-CAB-RBB). On July 24, 2018, the court consolidated the lawsuits and appointed Inter-Local Pension Fund GCC/IBT as lead plaintiff. On October 5, 2018, plaintiffs filed an amended complaint. The amended complaint alleges that we and certain of our executive officers made false and misleading statements and failed to disclose material adverse facts about our business, operations, and prospects in violation of Sections 10(b) (and Rule 10b-5 promulgated thereunder) and 20(a) of the Exchange Act. The amended complaint also alleges violations of Section 11 of the Exchange Act arising out of the Company’s initial public offering. The plaintiffs seek damages, interest, costs, attorneys' fees, and other unspecified equitable relief. The underwriters from our initial public offering have also been named as defendants in this case and we have certain obligations under the underwriting agreement to indemnify them for their costs and expenses incurred in connection with this litigation. On September 25, 2019, the court granted in part and denied in part the defendants’ motion to dismiss. The court dismissed the Section 11 claims entirely, without leave to amend, and accordingly dismissed the underwriters and certain directors from the case. The Court also dismissed certain statements from the Section 10 claims. The Company believes the remaining claims in the complaint are without merit and intend to defend vigorously against them.

Variable Interest Entity

Variable Interest Entity	12 Months Ended
Variable Interest Entity	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entity	Variable Interest Entity In conjunction with the Company’s strategic focus to open weight loss treatment centers to provide medical services to patients who wish to lose weight through the Obalon balloon system, the Company entered into a consulting agreement with a lead doctor to open the first treatment center and oversee the treatment center’s activities. The treatment center was opened in September 2019 as a professional corporation (“PC”) in the State of California and, as a result of state regulatory requirements, may not be owned by a corporation. The Company will fully fund all the activities of the treatment center and no financial contribution will be made by the lead doctor. In addition, the Company is authorized and expected to provide daily oversight of the activities of the center, with the exception of directly providing medical services. As the PC’s equity investment at risk is not sufficient to permit the entity to finance its activities without subordinated financial support, the PC is considered a variable interest entity. Although the Company does not own any equity interest in the PC, the Company holds the controlling financial interest as the sole funding source for the entity and through the ability to provide daily oversight. Therefore, the Company was determined to be the primary beneficiary of the PC and consolidated the PC’s balances and activity within its condensed consolidated financial statements. For the year ended December 31, 2019 , the PC recognized $0.2 million of deferred revenue associated with prepaid services at the treatment center, which is fully presented in the consolidated balance sheet of the Company at December 31, 2019 .

Restructuring Charges

Restructuring Charges	12 Months Ended
Restructuring Charges	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Restructuring Charges	Restructuring Charges 2019 Restructuring Activities In the second quarter of 2019, the Company recorded restructuring charges of $1.1 million , which are comprised of the following components (in thousands): Year Ended December 31, 2019 Employee separation costs $ 1,008 Asset disposals 91 Total $ 1,099 In April 2019, the Company notified approximately 49 employees whose employment will be terminated, or approximately 50% of its workforce, with the intent to refocus activities, streamline operations and make more efficient use of cash. As a result of the workforce reduction, the Company recorded a restructuring charge in April 2019 for termination benefits of $0.5 million which has been paid as of December 31, 2019. Additionally, as a result of the workforce reduction, the Company recognized a reversal of stock-based compensation expense of $0.8 million in April of 2019 and a $0.1 million restructuring charge in connection with the disposal of assets related to the terminated employees. In May and June 2019, the Company accepted the voluntary resignations of its President and Chief Executive Officer and its Vice President of Research and Development. As part of the resignations, each former officer entered into a consulting agreement for a term of 12 months, which allows for the continuous vesting of stock awards held over the consulting term and a monthly, fixed consulting fee. No severance amounts were granted. The Company recorded a restructuring charge in June 2019 for the full consulting benefits of $0.6 million of which $0.3 million has been paid as of December 31, 2019. Additionally, the Company recognized the full stock-based compensation expense of $0.7 million for these two former officers. No further restructuring charges were recorded in the third or fourth quarters of 2019. For the year ended December 31, 2019 , the following restructuring charges were included in the consolidated statements of operations and comprehensive loss as follows (in thousands): Year Ended December 31, 2019 Cost of revenue $ 53 Research and development 370 Selling, general and administrative 676 Total $ 1,099 Activity and restructuring charge reserve balance as of December 31, 2019 were as follows (in thousands): Employee separation costs Reserve balance at December 31, 2018 $ — 2019: Restructuring charges 1,099 Cash payments (819 ) Reserve balance at December 31, 2019 $ 280

Subsequent Events

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Equity Incentive Plan Restricted Stock Unit Awards On January 24, 2020, the Compensation Committee of the Company approved grants of restricted stock units under the 2016 Plan. Such restricted stock units were granted to certain executives at the Company in an aggregate amount of 816,081 restricted stock units, and may be settled in cash or stock in accordance with the terms of the awards. Each award will fully vest on the earlier of (i) December 31, 2022 and (ii) the consummation of a corporate transaction (as defined in the applicable award agreement), in each case, based on the achievement of stock price goals on the vesting date, subject to the executive's continued service with the Company through the vesting date. Treatment Centers - Orange County, CA and Sacramento, CA On January 24, 2020, the Company entered into a lease agreement with 1640 Newport Blvd. LP pursuant to which the Company has agreed to lease office space located in Orange County, at 1640 Newport Blvd. Costa Mesa, CA. The Company took possession of the office space on January 31, 2020, with the term of the lease agreement ending 62 months after such date, unless terminated earlier. The facility opened in February 2020. This facility serves as the second Obalon-branded treatment center location. On January 30, 2020, the Company entered into a lease agreement with Daniel L and Lyn S Monahan Trust pursuant to which the Company has agreed to lease office space located near Sacramento, at 1211 Pleasant Grove, Suite 100, Roseville, CA 95678. The lease commenced on February 1, 2020, with the term of the lease agreement ending 64 months after such date, unless terminated earlier. Lincoln Park Capital Fund, LLC Equity Line of Credit On February 5, 2020, the Company entered into a new purchase agreement (the “Purchase Agreement”) and registration rights agreement (the “Registration Rights Agreement”) with Lincoln Park Capital Fund, LLC (“Lincoln Park”), pursuant to which Lincoln Park has committed to purchase up to $15.0 million of the Company’s common stock, $0.001 par value per share (the “Common Stock”). The new Purchase Agreement replaces an existing purchase agreement, dated December 27, 2018, by and between the Company and Lincoln Park, pursuant to which Lincoln Park committed to purchase up to $20.0 million of the Company’s Common Stock. In connection with entering into the new Purchase Agreement, the Company and Lincoln Park terminated the prior purchase agreement, effective February 5, 2020. Under the terms and subject to the conditions of the Purchase Agreement, the Company has the right, but not the obligation, to sell to Lincoln Park, and Lincoln Park is obligated to purchase up to $15.0 million of the Company’s Common Stock. Such sales of common stock by the Company, if any, will be subject to certain limitations, and may occur from time to time, at the Company’s sole discretion, over the 36 -month period commencing on the date that a registration statement covering the resale of shares of Common Stock that have been and may be issued under the Purchase Agreement, which the Company agreed to file with the Securities and Exchange Commission (the “SEC”) pursuant to the Registration Rights Agreement, is declared effective by the SEC and a final prospectus in connection therewith is filed and the other conditions set forth in the purchase agreement are satisfied (such date on which all of such conditions are satisfied, the “Commencement Date”).

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of Obalon Therapeutics, Inc., and its wholly owned subsidiary, Obalon Center for Weight Loss, Inc. The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP, and include the Company's accounts and accounts of its wholly-owned subsidiary. The Company also consolidates variable interest entities (“VIE”) for which it is the primary beneficiary. The primary beneficiary has both (a) the power to direct the activities of the VIE that most significantly affect the entity’s economic performance and (b) either the obligation to absorb losses or the right to receive benefits. Refer to Note 11, “Variable Interest Entity” for further details. All intercompany transactions and balances have been eliminated in consolidation. The Company’s principal operations are located in Carlsbad, California and it operates in one business segment.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Reported amounts and note disclosures reflect the overall economic conditions that are most likely to occur and anticipated measures management intends to take. Actual results could differ materially from those estimates. All revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods affected.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents include cash in readily available checking and money market accounts.
Fair Value Measurements	Fair Value Measurements The carrying values of the Company’s financial instruments, including cash and cash equivalents, accounts receivable, accounts payable, and accrued expenses approximate their fair values due to the short maturity of these instruments. The carrying value of the term loan approximates its fair value as the interest rate and other terms are that which are currently available to the Company. The Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible. The Company determines fair value based on assumptions that market participants would use in pricing an asset or liability in the principal or most advantageous market. When considering market participant assumptions in fair value measurements, the following fair value hierarchy distinguishes between observable and unobservable inputs, which are categorized in one of the following levels in accordance with authoritative accounting guidance: ▪ Level 1 inputs: Observable inputs such as unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. ▪ Level 2 inputs: Other than quoted prices included in Level 1 inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the asset or liability. ▪ Level 3 inputs: Unobservable inputs for the asset or liability used to measure fair value to the extent that observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at measurement date.
Accounts Receivable	Accounts Receivable Receivables are unsecured and are carried at net realizable value including an allowance for estimated uncollectible amounts. Trade credit is generally extended on a short-term basis; thus trade receivables do not bear interest, although a finance charge may be applied to such receivables that are more than 30 days past due. The allowance for doubtful accounts is based on the Company’s assessment of the collectability of customer accounts. The Company regularly reviews the allowance by considering factors such as historical expense, credit quality, the age of the account receivable balances, and current economic conditions that may affect a customer’s ability to pay. Amounts determined to be uncollectible are charged or written off against the reserve.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash equivalents and trade accounts receivable, which are generally not collateralized. The Company limits its exposure to credit loss by placing its cash equivalents with high credit quality financial institutions and investing in high quality short-term debt instruments. The Company’s customers consist of physicians and institutions in the United States and one international distributor. The Company establishes customer credit policies related to its accounts receivable based on historical collection experiences within the various markets in which the Company operates, historical past-due amounts, and any specific information that the Company becomes aware of such as bankruptcy or liquidity issues of customers.
Inventory	Inventory Inventory is stated at the lower of cost (which approximates actual cost on a first-in, first-out basis) or net realizable value, computed on a standard cost basis. Inventory that is obsolete or is in excess of forecasted usage is written down to its estimated net realizable value based on assumptions about future demand. Inventory write-downs are charged to cost of revenue and establish a new cost basis for the inventory.
Property and Equipment	Property and Equipment Property and equipment are stated at cost and depreciated over the estimated useful lives of the assets. Maintenance and repairs are charged to expense as incurred. Assets not yet placed in use are not depreciated. The useful lives of the property and equipment are as follows: Computer hardware 3 years Computer software 3 years Leasehold improvements Shorter of lease term or useful life Furniture and fixtures 5 years Scientific equipment 5 years
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates property and equipment for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparison of the carrying amount of the assets to the future undiscounted net cash flows, which the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured as the difference between the carrying amount and the fair value of the impaired asset.
Leases	Leases Effective January 1, 2019, the Company adopted ASC No. 2016‑02, Leases (Topic 842) (“ASU 2016‑02” or “ASC 842”) , which supersedes the current accounting for leases, using the modified retrospective transition method. The Company has elected to apply the practical expedients allowed by the standard for existing leases. The new standard, while retaining two distinct types of leases, finance and operating, (i) requires lessees to record a right-of-use (“ROU”) asset and a related liability for the rights and obligations associated with a lease, regardless of lease classification, and recognize lease expense in a manner similar to current accounting, (ii) eliminates current real estate specific lease provisions, (iii) modifies the lease classification criteria and (iv) aligns many of the underlying lessor model principles with those in the new revenue standard. The Company determines the initial classification and measurement of its ROU asset and lease liabilities at the lease commencement date and thereafter, if modified. The Company recognizes a ROU asset for its operating leases with lease terms greater than 12 months. The lease term includes any renewal options and termination options that the Company is reasonably assured to exercise. The present value of lease payments is determined by using the incremental borrowing rate for operating leases determined by using the incremental borrowing rate of interest that the Company would pay to borrow on a collateralized basis an amount equal to the lease payments in a similar economic environment and term. The Company applied the new guidance to its existing facility lease at the time of adoption and recognized a ROU asset and lease liability of $1.2 million and $1.3 million , respectively, during the first quarter of 2019. The Company recorded an immaterial amount of lease liabilities, ROU assets, and interest expense associated with finance leases as of and for the year ended December 31, 2019. The current and long-term portions of finance lease liabilities are presented within the current portion of lease liabilities and lease liabilities long-term line items on the consolidated balance sheet, respectively. Finance lease ROU assets are presented within the lease right-of-use assets line item on the consolidated balance sheet. Rent expense for operating leases is recognized on a straight-line basis over the reasonably assured lease term based on the total lease payments and is included in research and development and general and administrative expenses in the statements of operations.
Variable Interest Entities	Variable Interest Entities The Company evaluates its ownership, contractual and other interests in entities that are not wholly-owned to determine if these entities are VIEs, and, if so, whether the Company is the primary beneficiary of the VIE. In determining whether the Company is the primary beneficiary of a VIE and therefore required to consolidate the VIE, the Company applies a qualitative approach that determines whether the Company has both (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (2) the obligation to absorb losses of, or the rights to receive benefits from, the VIE that could potentially be significant to that VIE. The Company continuously assesses whether it is the primary beneficiary of a VIE, as changes to existing relationships or future transactions may result in the consolidation or deconsolidation of such VIE.
Research and Development Costs	Research and Development Costs All research and development costs are charged to expense as incurred. Research and development expenses primarily include (i) payroll and related costs associated with research and development performed, (ii) costs related to clinical and preclinical testing of our technologies under development and (iii) other research and development expenses.
Clinical Trial Expenses	Clinical Trial Expenses The Company enters into contracts with third party hospitals and doctors to perform clinical trial activities. The Company accrues expenses for clinical trial activities performed by third parties based on estimates of work performed by each third party as of the balance sheet date. The Company’s clinical trial expense is primarily driven by patient visits to the third party hospitals and doctors. As such, the Company accrues expense for actual patient visits based on third-party reporting and the contractually agreed upon cost for each visit to calculate its clinical accrual.
Stock-Based Compensation	Stock-Based Compensation Stock-based awards issued to employees and directors, are recorded at fair value as of the grant date and recognized as expense on a ratable basis over the employee’s or director’s requisite service period (generally the vesting period). The fair value of incentive stock options is estimated using the Black-Scholes option pricing model. The fair value of restricted stock awards and restricted stock units is estimated using the Company's stock price on the grant date. Because non-cash stock compensation expense is based on awards ultimately expected to vest, it is reduced by an estimate for future forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates.
Income Taxes	Income Taxes Income taxes are accounted for under the asset-and-liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is greater than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. Valuation allowances are established, when necessary, to reduce deferred tax assets to the amount expected to be realized. The Company accounts for interest and penalties related to income tax matters, if any, as a component of income tax expense or benefit.
Revenue Recognition	Revenue recognition The Company recognizes revenue, in accordance with ASC 606, when control of its products is transferred to its customers in an amount that reflects the consideration it expects to receive in exchange for those products. The Company's revenue recognition process involves identifying the contract with a customer, determining the performance obligations in the contract, determining the transaction price, allocating the transaction price to the distinct performance obligations in the contract, and recognizing revenue as performance obligations are satisfied. A performance obligation is considered distinct from other obligations in a contract when it provides a benefit to the customer either on its own or together with other resources that are readily available to the customer and is separately identified in the contract. The Company considers a performance obligation satisfied once it has transferred control of a good or service to the customer, meaning the customer has the ability to use and obtain the benefit of the good or service. The Company recognizes revenue for satisfied performance obligations only when it determines there are no uncertainties regarding payment terms or transfer of control. Revenue is primarily generated from sales of the Obalon Balloon System to physicians and institutions in the United States, patients treated at the Obalon branded retail center, and sales to distributors in the Middle East. In sales to these customers, the Company recognizes revenue upon shipment of its product as the Company's standard contract terms dictate that control transfers to the customer upon shipment of its product. Invoicing typically occurs upon shipment and the time period between invoicing and when payment is due is not significant. Sales taxes collected are excluded from revenues. Shipping charges billed to customers are included in revenue and related shipping cost is included in cost of revenue. The Company's revenue contracts do not provide for maintenance. Revenue generated from the treatment centers that began treating patients in October 2019 is recognized as the distinct service performance obligations are delivered to customers. Commissions are considered incremental costs to obtain a contract with a customer and paid to salespeople when contracts are executed. Commissions from both private practice and treatment center revenues are recognized as a selling expense when incurred as the amortization period is one year or less. The components of the Obalon Balloon System, in sales to physicians and Middle East distributors, are typically packaged in a kit and shipped to the customer at the same time, satisfying the majority of performance obligations in the contract. Revenues from the treatment center are recognized as the Company delivers the distinct performance obligations. The Company records deferred revenue at the treatment center whenever the Company receives cash payments prior to the fulfillment of the distinct performance obligations. The Company recognizes revenue for any unsatisfied, distinct performance obligations, such as undelivered components, as they are satisfied based on the estimated standalone selling price of each performance obligation. The Company estimates the standalone selling price of each performance obligation by estimating the expected cost of satisfying that performance obligation plus an appropriate margin and also third-party evidence for certain performance obligations from treatment center revenues. When the Company enters into contracts with multiple performance obligations, such obligations are generally satisfied within a short time frame of approximately three to six months after the contract execution date. The Company does not disclose the value of the unsatisfied performance obligations within its contracts. The Company offers a swallow guarantee program in the United States where it may provide replacement balloons to customers when their patients are unsuccessful in swallowing an Obalon balloon, subject to certain requirements and restrictions. The Company considers the replacement balloons provided under this program as an additional performance obligation in the contract and defers revenue relating to the replacement balloons based on an expected swallow failure rate and then recognizes revenue when replacement balloons are provided. The Company recognizes revenue at the net sales price, which reflects the consideration the Company believes it is most likely to receive. The net sales price includes estimates of variable consideration for customer incentives and returns. The Company reserves for product returns as a reduction to revenue in the period when the related revenue is recognized. The Company estimates its product returns based on historical return rates and specifically known events. Estimated costs of customer incentive programs are recorded at the time the incentives are offered, based on the specific terms and conditions of the program. Customer incentives that provide discounts to the customer on purchases of current or future product are recorded as a reduction of revenue in the period the related product revenue is recognized. Any consideration payable to a customer is presumed as a reduction to revenue unless the Company can demonstrate that the consideration provided to the customer is in exchange for a distinct good or service. Actual amounts of consideration ultimately received may differ from the Company’s estimates. If actual results vary from the Company’s estimates, the Company would adjust these estimates, which would impact net product revenue and results of operations in the period such variances become known.
Product Warranty	Product Warranty The Company warranties its products to be of good quality and free from defects in design, materials, or workmanship for approximately one year from the date of purchase. The Company accrues for the estimated future costs of repair or replacement upon shipment. The warranty accrual is recorded to cost of revenue and is based on historical and forecasted trends in the volume of product failures during the warranty period and the cost to repair or replace the equipment. It is possible that the Company’s underlying assumptions will not reflect the actual experience and in that case, future adjustments will be made to the recorded warranty obligation.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred and included in selling, general and administrative expense.
Net Loss per Share	Net Loss per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period without consideration for common stock equivalents. Diluted net loss per share is the same as basic net loss per common share, since the effects of potentially dilutive securities are anti-dilutive due to the net loss position of all periods presented. Potentially dilutive common stock equivalents are comprised of warrants, unvested restricted stock awards (RSAs), and unexercised stock options outstanding under the Company's equity plan.
Recently Issued and Adopted Accounting Pronouncements	Recently Issued and Adopted Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board, or FASB, or other standard setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption. Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). Under this new guidance, at the commencement date, lessees will be required to recognize (i) a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis and (ii) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. This guidance is not applicable for leases with a term of 12 months or less. In July 2018, the FASB issued ASU 2018-10, Codification Improvements to Topic 842 (Leases), which provides narrow amendments to clarify how to apply certain aspects of the new lease standard. The new standard is effective for annual reporting periods, and interim periods within those periods, beginning after December 15, 2018, with early adoption permitted. In July 2018, the FASB issued ASU No. 2018-11, Leases Topic (842): Targeted Improvements. This ASU provides companies an option to apply the transition provisions of the new lease standard at its adoption date instead of at the earliest comparative period presented in its financial statements. The Company elected the optional method to account for the impact of the adoption with a cumulative-effect adjustment in the period of adoption, if needed, and did not restate prior periods. The Company elected certain practical expedients permitted under the transition guidance. As part of the adoption, the Company recorded a ROU asset and liability upon adoption of the guidance pertaining to its long-term real estate lease for its corporate facilities. No cumulative-effect adjustment was needed. In February 2018, the FASB issued Accounting Standards Update ("ASU") 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220). The new guidance permits, but does not require, companies to reclassify the stranded tax effects of the Tax Cuts and Jobs Act on items within accumulated other comprehensive income to retained earnings. The Company adopted this standard in the first quarter of 2019, which did not have a material impact on its consolidated financial statements. Recently Issued Accounting Pronouncements not yet adopted In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13, Financial Instruments - Credit Losses, which changes the accounting for recognizing impairments of financial assets. Under the new guidance, credit losses for certain types of financial instruments will be estimated based on expected losses. The new guidance also modifies the impairment models for available-for-sale debt securities and for purchased financial assets with credit deterioration since their origination. In February 2020, the FASB issued ASU 2020-02, Financial Instruments-Credit Losses (Topic 326) and Leases (Topic 842) - Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 119 and Update to SEC Section on Effective Date Related to Accounting Standards Update No. 2016-02, Leases (Topic 842) , which amends the effective date of the original pronouncement for smaller reporting companies. ASU 2016-13 and its amendments will be effective for the Company for interim and annual periods in fiscal years beginning after December 15, 2022. The Company believes the adoption will modify the way the Company analyzes financial instruments, but it does not anticipate a material impact on results of operations. The Company is in the process of determining the effects the adoption will have on its consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820); Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. This guidance removes certain disclosure requirements related to the fair value hierarchy, modifies existing disclosure requirements related to measurement uncertainty and adds new disclosure requirements. The new disclosure requirements include disclosing the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and the range and weighted-average of significant unobservable inputs used to develop Level 3 fair value measurements. Certain disclosures required by this guidance must be applied on a retrospective basis and others on a prospective basis. The guidance will be effective for fiscal years beginning after December 15, 2019, although early adoption is permitted. The Company is currently evaluating this guidance to determine the impact, if any, it may have on its consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
Summary of Significant Accounting Policies (Tables)	Dec. 31, 2019
Accounting Policies [Abstract]
Schedules of Concentration of Risk by Risk Factor	The following table summarizes certain financial data for the customers who accounted for 10.0% or more of sales and accounts receivable. Year ended December 31, Revenue 2019 2018 Customer A 19.7 % 3.4 % Customer B 17.9 % 48.4 % Customer C — % 14.1 % Accounts Receivable December 31, 2019 December 31, 2018 Customer A 20.8 % 2.1 % Customer B — % — % Customer C — % 0.7 % The Company's largest customer for the year ended December 31, 2019 was a U.S. physician, and for the year ended December 31, 2018 the largest customer was its Middle East distributor in Kuwait.
Estimated Useful Lives of Property, Plant and Equipment	The useful lives of the property and equipment are as follows: Computer hardware 3 years Computer software 3 years Leasehold improvements Shorter of lease term or useful life Furniture and fixtures 5 years Scientific equipment 5 years Property and equipment, net consist of the following (in thousands): December 31, 2019 2018 Computer hardware $ 263 $ 410 Computer software 291 274 Leasehold improvements 497 405 Furniture and fixtures 247 178 Scientific equipment 1,999 1,921 Construction in progress, or CIP 110 530 3,407 3,718 Less: accumulated depreciation (2,326 ) (1,979 ) Total $ 1,081 $ 1,739

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
Fair Value Measurements (Tables)	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis at December 31, 2019 and 2018 are as follows (in thousands): Fair value measurements at reporting date using Balance as of December 31, 2019 Quoted prices Significant Significant Assets: Cash $ 1,012 $ 1,012 Cash Equivalents: Money Market Funds 13,043 13,043 — — Total assets $ 14,055 $ 14,055 $ — $ — Fair value measurements at reporting date using Balance as of December 31, 2018 Quoted prices in active Significant (Level 2) Significant (Level 3) Assets: Cash $ 18,384 $ 18,384 Cash Equivalents: Money Market Funds 2,803 2,803 — — Short-term investments: U.S. Treasury bonds 2,548 2,548 — — Total assets $ 23,735 $ 23,735 $ — $ —

Net Loss per Share (Tables)

Net Loss per Share (Tables)	12 Months Ended
Net Loss per Share (Tables)	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss per Share of Common Stock	The following table sets forth the computation of basic and diluted net loss per share of common stock (in thousands, except shares and per share data): Year ended December 31, 2019 2018 Net loss $ (23,676 ) $ (37,380 ) Weighted-average common shares outstanding, basic and diluted 4,706,775 1,903,734 Net loss per share, basic and diluted $ (5.03 ) $ (19.64 )
Schedule of Anti-Dilutive Common Stock Equivalents Excluded from the Calculation of Diluted Net Loss Per Share	The following table sets forth the outstanding potentially dilutive securities determined using the treasury stock method that have been excluded in the calculation of diluted net loss per share because to do so would be anti-dilutive (in common stock equivalent shares): Year ended December 31, 2019 2018 Stock options to purchase common stock 8,900 38,352 Total 8,900 38,352

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	12 Months Ended
Balance Sheet Details (Tables)	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Schedule of Inventory	Inventory consists of the following (in thousands): December 31, 2019 2018 Raw materials $ 1,835 $ 1,090 Work in process 12 288 Finished goods 89 202 Total $ 1,936 $ 1,580
Schedule of Other Current Assets	Other current assets consist of the following (in thousands): December 31, 2019 2018 Prepaid expenses $ 1,890 $ 2,329 Interest receivable 0 12 Other assets 69 121 Total $ 1,959 $ 2,462
Schedule of Property and Equipment, Net	The useful lives of the property and equipment are as follows: Computer hardware 3 years Computer software 3 years Leasehold improvements Shorter of lease term or useful life Furniture and fixtures 5 years Scientific equipment 5 years Property and equipment, net consist of the following (in thousands): December 31, 2019 2018 Computer hardware $ 263 $ 410 Computer software 291 274 Leasehold improvements 497 405 Furniture and fixtures 247 178 Scientific equipment 1,999 1,921 Construction in progress, or CIP 110 530 3,407 3,718 Less: accumulated depreciation (2,326 ) (1,979 ) Total $ 1,081 $ 1,739
Schedule of Other Current Liabilities	Other current liabilities consist of the following (in thousands): December 31, 2019 2018 Accrued legal and professional fees $ 412 $ 624 Accrued customer incentives 198 467 Accrued sales and other taxes 107 132 Returns reserve liability 315 214 Other accrued expenses 492 548 Total $ 1,524 $ 1,985

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
Stock-Based Compensation (Tables)	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Summary of Non-cash Compensation to Employees and Nonemployees in Condensed Consolidated Statements of Operations and Comprehensive Loss	The Company recorded total non-cash compensation, including non-cash compensation to employees and nonemployees in the consolidated statements of operations and comprehensive loss as follows (in thousands): Year ended December 31, 2019 2018 Cost of revenue $ (21 ) $ 96 Research and development 739 1,141 Selling, general and administrative 2,265 3,456 Total $ 2,983 $ 4,693
Summary of Fair Value of Stock Options for Employees was Estimated using Black-Scholes Option Pricing Model	The fair value of each option granted was estimated on the date of grant using the Black-Scholes option pricing model using the following assumptions: Year ended December 31, 2019 2018 Assumed risk-free interest rate (1) 1.67% - 2.58% 2.31% - 3.10% Assumed volatility (2) 55.07% - 65.21% 53.95% - 55.44% Expected option life (3) 6.1 years 5.0 - 6.1 years Expected dividend yield (4) —% —% (1) The risk-free interest rate was determined based on the U.S. Treasury yield in effect at the time of the grant for zero-coupon U.S. Treasury notes with remaining terms similar to the expected term of the options. (2) The volatility was determined based on analysis of the volatility of a peer group of publicly traded companies as the Company's stock has not traded publicly for a significant time and the Company has limited company specific historical volatility. The peer group was determined considering factors such as stage of development, risk profile, enterprise value and position within the industry. (3) The expected option life was determined using the “simplified method” for estimating the expected option life, which is the average of the weighted-average vesting period and contractual term of the option. (4) The expected dividend yield was zero as the Company has not historically issued dividends and does not expect to do so in the foreseeable future.
Summary of Stock Option Transactions	The following table summarizes stock option transactions for the 2016 Plan for the year ended December 31, 2019 (in thousands, except shares and per share data): Number of Weighted- Weighted- (in years) Aggregate Outstanding at December 31, 2018 336,008 $ 58.29 Options granted 237,197 12.13 Options exercised (118 ) 8.72 Options canceled (54,619 ) 44.46 Outstanding at December 31, 2019 518,468 38.64 6.8 $ 12 Vested and expected to vest at December 31, 2019 475,431 $ 40.60 6.6 $ 9 Vested and exercisable at December 31, 2019 270,613 $ 52.72 6.1 $ 0.3
Summary of Restricted Stock Awards	The following table summarizes restricted stock award transactions for the year ended December 31, 2019 : Number of awards Weighted- average grant date fair value Outstanding at December 31, 2018 61,198 $ 58.85 Awards granted — — Awards released (4,750 ) 71.50 Awards canceled (26,924 ) 77.70 Outstanding at December 31, 2019 29,524 $ 39.64
Summary of Restricted Stock Unit Transactions	The following table summarizes restricted stock unit transactions for the 2016 Plan for the year ended December 31, 2019: Number of shares Weighted-average grant date fair value Aggregate intrinsic value (in thousands) Outstanding at December 31, 2018 — $ — Awards granted 55,574 11.70 Awards released — — Awards canceled — — Outstanding at December 31, 2019 55,574 $ 11.70 $ 106 Vested and expected to vest at December 31, 2019 51,894 $ 11.84 $ 99

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
Stockholders' Equity (Tables)	Dec. 31, 2019
Equity [Abstract]
Schedule of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance consists of the following at December 31, 2019 : Stock options issued and outstanding 518,468 Restricted stock units issued and outstanding 55,574 Warrants for the purchase of common stock 3,271,875 Authorized for future option and ongoing vesting of award grants 5,337 Authorized for future issuance under ESPP 74,520 Total 3,925,774

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Provision (Benefit)	The income tax provision consists of the following (in thousands): Year ended December 31, 2019 2018 Current: Federal $ — $ — State 14 11 Total current provision 14 11 Deferred: Federal — — State — — Total deferred provision — — Income tax provision $ 14 $ 11
Schedule of Effective Income Tax Rate Reconciliation	The difference between income tax benefits and income taxes computed using the U.S. federal income tax rate as of December 31, 2019 and 2018 are as follows (in thousands): Year ended December 31, 2019 2018 Federal provision (benefit) At statutory rates $ (4,971 ) $ (7,848 ) Change in valuation allowance 4,985 7,859 Income tax provision $ 14 $ 11
Schedule of Deferred Tax Assets	Significant components of the Company’s deferred tax assets and liabilities are as shown below (in thousands): Year ended December 31, 2019 2018 Deferred tax assets: Net operating losses $ 35,252 $ 28,708 Tax credits 5,493 4,898 Capitalized research and development costs 2,401 2,566 Other 2,724 2,458 Total gross deferred tax assets 45,870 38,630 Less valuation allowance (45,578 ) (38,630 ) Total deferred tax assets $ 292 $ — Deferred tax liabilities: Other $ (292 ) $ — Total deferred tax liabilities $ (292 ) $ —
Summary of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows (in thousands): Year ended December 31, 2019 2018 Balance at January 1 $ 3,609 $ 2,128 Additions based on tax positions related to current year 643 1,513 Additions based on tax positions related to prior years — — Reductions for tax positions related to prior years (2 ) (32 ) Balance at December 31 $ 4,250 $ 3,609

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
Commitments and Contingencies (Tables)	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Future minimum lease payments under operating leases	Future minimum annual lease payments under such leases were as follows as of December 31, 2019 (in thousands): Operating leases: 2020 $ 537 2021 517 2022 117 Total undiscounted lease payments - operating leases $ 1,171 Finance leases: 2020 $ 24 2021 24 Total undiscounted lease payments - finance leases $ 48 Total undiscounted lease payments $ 1,219 Less: imputed interest $ (91 ) Lease liability $ 1,128 Less: current portion of lease liability $ (561 ) Lease liability, less current portion $ 567
Future minimum lease payments under finance leases	Future minimum annual lease payments under such leases were as follows as of December 31, 2019 (in thousands): Operating leases: 2020 $ 537 2021 517 2022 117 Total undiscounted lease payments - operating leases $ 1,171 Finance leases: 2020 $ 24 2021 24 Total undiscounted lease payments - finance leases $ 48 Total undiscounted lease payments $ 1,219 Less: imputed interest $ (91 ) Lease liability $ 1,128 Less: current portion of lease liability $ (561 ) Lease liability, less current portion $ 567

Restructuring Charges (Tables)

Restructuring Charges (Tables)	12 Months Ended
Restructuring Charges (Tables)	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	No further restructuring charges were recorded in the third or fourth quarters of 2019. For the year ended December 31, 2019 , the following restructuring charges were included in the consolidated statements of operations and comprehensive loss as follows (in thousands): Year Ended December 31, 2019 Cost of revenue $ 53 Research and development 370 Selling, general and administrative 676 Total $ 1,099 In the second quarter of 2019, the Company recorded restructuring charges of $1.1 million , which are comprised of the following components (in thousands): Year Ended December 31, 2019 Employee separation costs $ 1,008 Asset disposals 91 Total $ 1,099
Activity and Restructuring Charge Reserve Balance	Activity and restructuring charge reserve balance as of December 31, 2019 were as follows (in thousands): Employee separation costs Reserve balance at December 31, 2018 $ — 2019: Restructuring charges 1,099 Cash payments (819 ) Reserve balance at December 31, 2019 $ 280

Organization and Basis of Pre_2

Organization and Basis of Presentation - Additional Information (Detail)	Aug. 01, 2019USD ($)shares	Jul. 24, 2019shares	Apr. 02, 2019employee	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Sep. 30, 2019shares	Dec. 31, 2019USD ($)segment$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 27, 2018USD ($)	Jun. 30, 2018shares	May 31, 2018shares
Basis Of Presentation And Organization [Line Items]
Number of operating segments \| segment							1
Reverse stock split conversion ratio		0.10
Common stock, shares authorized (in shares)		100,000,000					100,000,000	300,000,000		100,000,000	300,000,000
Revenue \| $							$ 3,281,000	$ 9,101,000
Accumulated deficit \| $							(172,430,000)	(148,754,000)
Cash and cash equivalents \| $							14,055,000	21,187,000
Payment on long-term loan \| $							$ 20,000,000	$ 0
Number of employees terminated \| employee			49
Percent of workforce terminated			50.00%
Common stock, par value (in dollars per share) \| $ / shares							$ 0.001	$ 0.001
Public Stock Offering
Basis Of Presentation And Organization [Line Items]
Number of shares sold (in shares)	2,427,500
Proceeds from issuance of common stock and common stock warrants \| $	$ 14,700,000
Over-Allotment Option
Basis Of Presentation And Organization [Line Items]
Number of shares sold (in shares)	412,500
Pursuant to Partial Exercise
Basis Of Presentation And Organization [Line Items]
Number of shares sold (in shares)	562,500
Canaccord Genuity, LLC \| Equity Distribution Agreement
Basis Of Presentation And Organization [Line Items]
Number of shares sold (in shares)						377,615
Maximum purchase commitment \| $								$ 10,000,000	$ 10,000,000
Line of Credit \| Fifth Amendment To The Loan And Security Agreement Tranche One
Basis Of Presentation And Organization [Line Items]
Payment on long-term loan \| $				$ 5,000,000	$ 15,000,000
Pre-Funded Warrants \| Maximum \| Public Stock Offering
Basis Of Presentation And Organization [Line Items]
Shares of common stock to be purchased (in shares)	1,735,000
Firm Warrants \| Maximum \| Public Stock Offering
Basis Of Presentation And Organization [Line Items]
Shares of common stock to be purchased (in shares)	3,234,375
Firm Warrants \| Maximum \| Over-Allotment Option
Basis Of Presentation And Organization [Line Items]
Shares of common stock to be purchased (in shares)	421,875
Representative Warrants \| Public Stock Offering
Basis Of Presentation And Organization [Line Items]
Shares of common stock to be purchased (in shares)	37,500

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unrealized losses on short term investments	$ 0	$ 0	$ 0
Realized gain (loss) on short term investments	0	0	$ 0
Allowance for doubtful accounts	$ 500	700
Revenue, performance obligation, description of timing	When the Company enters into contracts with multiple performance obligations, such obligations are generally satisfied within a short time frame of approximately three to six months after the contract execution date.
Advertising expense	$ 800	$ 3,800
Lease right-of-use assets	1,077
Operating lease liability	$ 1,128
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease right-of-use assets				$ 1,200
Operating lease liability				$ 1,300

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Concentration Risk (Details) - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Customer A \| Revenue
Concentration Risk [Line Items]
Concentration risk percentage	19.70%	3.40%
Customer A \| Accounts Receivable
Concentration Risk [Line Items]
Concentration risk percentage	20.80%	2.10%
Customer B \| Revenue
Concentration Risk [Line Items]
Concentration risk percentage	17.90%	48.40%
Customer B \| Accounts Receivable
Concentration Risk [Line Items]
Concentration risk percentage	0.00%	0.00%
Customer C \| Revenue
Concentration Risk [Line Items]
Concentration risk percentage	0.00%	14.10%
Customer C \| Accounts Receivable
Concentration Risk [Line Items]
Concentration risk percentage	0.00%	0.70%

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2019
Computer hardware
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Computer software
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Scientific equipment
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	$ 14,055	$ 23,735
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	14,055	23,735
Significant other observable inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	0	0
Significant unobservable inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	0	0
Cash
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value disclosure	1,012	18,384
Cash \| Quoted prices in active markets for identical assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value disclosure	1,012	18,384
Money Market Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value disclosure	13,043	2,803
Money Market Funds \| Quoted prices in active markets for identical assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value disclosure	13,043	2,803
Money Market Funds \| Significant other observable inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value disclosure	0	0
Money Market Funds \| Significant unobservable inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, fair value disclosure	$ 0	0
U.S. Treasury bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments		2,548
U.S. Treasury bonds \| Quoted prices in active markets for identical assets (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments		2,548
U.S. Treasury bonds \| Significant other observable inputs (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments		0
U.S. Treasury bonds \| Significant unobservable inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments		$ 0

Net Loss per Share - Schedule o

Net Loss per Share - Schedule of Computation of Basic and Diluted Net Loss Per Share of Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net loss	$ (23,676)	$ (37,380)
Weighted-average common shares outstanding, basic and diluted (in shares)	4,706,775	1,903,734
Net loss per share, basic and diluted (in dollars per share)	$ (5.03)	$ (19.64)

Net Loss per Share - Schedule_2

Net Loss per Share - Schedule of Anti-Dilutive Common Stock Equivalents Excluded from the Calculation of Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share (in shares)	8,900	38,352
Stock options to purchase common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of diluted net loss per share (in shares)	8,900	38,352

Balance Sheet Details - Schedul

Balance Sheet Details - Schedule of Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Raw materials	$ 1,835	$ 1,090
Work in process	12	288
Finished goods	89	202
Total	$ 1,936	$ 1,580

Balance Sheet Details - Sched_2

Balance Sheet Details - Schedule of Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Prepaid expenses	$ 1,890	$ 2,329
Interest receivable	0	12
Other assets	69	121
Total	$ 1,959	$ 2,462

Balance Sheet Details - Sched_3

Balance Sheet Details - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,407	$ 3,718
Less: accumulated depreciation	(2,326)	(1,979)
Property and equipment, net	1,081	1,739
Computer hardware
Property, Plant and Equipment [Line Items]
Property and equipment, gross	263	410
Computer software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	291	274
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	497	405
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	247	178
Scientific equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,999	1,921
Construction in progress, or CIP
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 110	$ 530

Balance Sheet Details - Additio

Balance Sheet Details - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Depreciation	$ 479	$ 581

Balance Sheet Details - Sched_4

Balance Sheet Details - Schedule of Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Accrued legal and professional fees	$ 412	$ 624
Accrued customer incentives	198	467
Accrued sales and other taxes	107	132
Returns reserve liability	315	214
Other accrued expenses	492	548
Total	$ 1,524	$ 1,985

Term Loan - Additional Informat

Term Loan - Additional Information (Details)	1 Months Ended	3 Months Ended			9 Months Ended	12 Months Ended
Term Loan - Additional Information (Details)	Jul. 31, 2018USD ($)tranche	Sep. 30, 2019USD ($)installment	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Sep. 30, 2019installment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Aug. 31, 2019	Jun. 30, 2018USD ($)	Jun. 30, 2013USD ($)
Debt Instrument [Line Items]
Repayments of long-term debt						$ 20,000,000	$ 0
2013 Loan Agreement
Debt Instrument [Line Items]
Term loan, maximum borrowings										$ 3,000,000
5th Amendment To The Loan And Security Agreement \| Line of Credit
Debt Instrument [Line Items]
Term loan, maximum borrowings	$ 20,000,000
Number of tranches \| tranche	2
December 2016 Loan Agreement
Debt Instrument [Line Items]
Borrowings outstanding						0
Term loan, effective interest rate		7.00%			7.00%
Number of installments \| installment		36			36
December 2016 Loan Agreement \| Prime Rate
Debt Instrument [Line Items]
Term loan, variable interest rate					1.50%
Term loan, fixed interest rate								5.50%
December 2016 Loan Agreement \| Line of Credit
Debt Instrument [Line Items]
Term loan, maximum borrowings									$ 10,000,000
5th Amendment To The Loan And Security Agreement Tranche 1 \| Line of Credit
Debt Instrument [Line Items]
Term loan, maximum borrowings	$ 10,000,000
Proceeds used for repayment of debt	10,000,000
Repayments of long-term debt		$ 5,000,000	$ 15,000,000
Unamortized debt issuance costs						$ 0
5th Amendment To The Loan And Security Agreement Tranche 2 \| Line of Credit
Debt Instrument [Line Items]
Term loan, maximum borrowings	$ 10,000,000
Proceeds from debt				$ 10,000,000
Minimum \| December 2016 Loan Agreement
Debt Instrument [Line Items]
Term loan, fixed interest rate		5.00%			5.00%

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 05, 2016	Oct. 04, 2016	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance (in shares)			3,925,774
Unrecognized compensation expense			$ 1.7
Weighted average compensation cost recognition period			2 years 4 months 24 days
Weighted-average fair value of options granted (in dollars per share)			$ 6.81
Intrinsic value of options exercised in period				$ 0.1
Stock options early exercised (in shares)			0	0
Stock options remaining, unvested (in shares)			1,383
Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance (in shares)					223,673
2016 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance (in shares)			5,337
Shares reserved for issuance, increase percentage of common stock outstanding and common stock equivalents		4.00%
Award vesting percentage			25.00%
Vesting period			3 years
2016 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance (in shares)	74,520		74,520
Shares reserved for issuance, increase percentage of common stock outstanding and common stock equivalents	1.00%
Number of years shares reserved for issuance increases automatically	10 years
Shares issued in period (in shares)			0	4,526
Unvested restricted common stock awards \| 2016 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average compensation cost recognition period			1 year 6 months
Award vesting percentage			100.00%
Vesting period			10 years
Share-based compensation expense			$ 0.1
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance (in shares)			55,574
Restricted Stock Units (RSUs) \| 2016 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average compensation cost recognition period			7 months 6 days
Award vesting percentage			100.00%
Share-based compensation expense			$ 0.2

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Non-cash Compensation to Employees and Nonemployees in Condensed Consolidated Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation	$ 2,983	$ 4,693
Cost of revenue
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation	(21)	96
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation	739	1,141
Selling, general and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation	$ 2,265	$ 3,456

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Fair Value of Stock Options for Employees was Estimated using Black-Scholes Option Pricing Model (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected option life	6 years 1 month 6 days
Expected dividend yield	0.00%	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Assumed risk-free interest rate	1.67%	2.31%
Assumed volatility	55.07%	53.95%
Expected option life		5 years
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Assumed risk-free interest rate	2.58%	3.10%
Assumed volatility	65.21%	55.44%
Expected option life		6 years 1 month 6 days

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Stock Option Transactions (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of shares outstanding, beginning balance (in shares) \| shares	336,008
Number of shares, options granted (in shares) \| shares	237,197
Number of shares, options exercised (in shares) \| shares	(118)
Number of shares, options canceled (in shares) \| shares	(54,619)
Number of shares outstanding, ending balance (in shares) \| shares	518,468
Number of shares, vested and expected to vest at end of period (in shares) \| shares	475,431
Number of shares, vested and exercisable at period end (in shares) \| shares	270,613
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price outstanding, beginning balance (in dollars per share) \| $ / shares	$ 58.29
Weighted average exercise price, options granted (in dollars per share) \| $ / shares	12.13
Weighted average exercise price, options exercised (in dollars per share) \| $ / shares	8.72
Weighted average exercise price, options canceled (in dollars per share) \| $ / shares	44.46
Weighted average exercise price outstanding, ending balance (in dollars per share) \| $ / shares	38.64
Weighted average exercise price, vested and expected to vest (in dollars per share) \| $ / shares	40.60
Weighted average exercise price, vested and exercisable (in dollars per share) \| $ / shares	$ 52.72
Weighted average contractual life outstanding, ending balance	6 years 9 months 15 days
Weighted average contractual life, vested and expected to vest	6 years 6 months 22 days
Weighted average contractual life, vested and exercisable	6 years 29 days
Aggregate intrinsic value outstanding \| $	$ 12
Aggregate intrinsic value, vested and expected to vest \| $	9
Aggregate intrinsic value, vested and exercisable \| $	$ 0

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Restricted Stock Awards (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Weighted- average grant date fair value
Vested and expected to vest, number of shares (in shares)	51,894
Vested and expected to vest, weighted average grant date fair value (in dollars per share)	$ 11.84
Vested and expected to vest, aggregate intrinsic value	$ 99
Restricted Stock
Number of awards
Outstanding, beginning balance (in shares)	61,198
Awards granted (in shares)	0
Awards released (in shares)		(4,750)
Awards canceled (in shares)	(26,924)
Outstanding, ending balance (in shares)	29,524	61,198
Weighted- average grant date fair value
Outstanding, beginning balance (in dollars per share)	$ 58.85
Awards granted (in dollars per share)	0
Awards released (in dollars per share)		$ 71.50
Awards canceled (in dollars per share)	77.70
Outstanding, ending balance (in dollars per share)	$ 39.64	$ 58.85
Restricted Stock Units (RSUs)
Number of awards
Outstanding, beginning balance (in shares)	0
Awards granted (in shares)	55,574
Awards released (in shares)	0
Awards canceled (in shares)	0
Outstanding, ending balance (in shares)	55,574	0
Weighted- average grant date fair value
Outstanding, beginning balance (in dollars per share)	$ 0
Awards granted (in dollars per share)	11.70
Awards released (in dollars per share)	0
Awards canceled (in dollars per share)	0
Outstanding, ending balance (in dollars per share)	$ 11.70	$ 0
Shares outstanding, aggregate intrinsic value	$ 106

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($)

Feb. 05, 2020

Aug. 01, 2019

May 23, 2019

Dec. 27, 2018

Aug. 31, 2019

Sep. 30, 2019

Dec. 31, 2019

Feb. 29, 2020

Aug. 06, 2019

Jul. 24, 2019

Dec. 31, 2018

Dec. 26, 2018

Jun. 30, 2018

May 31, 2018

Class of Stock [Line Items]

Common stock, shares authorized (in shares)

100,000,000

300,000,000

100,000,000

300,000,000

Stock issued during period, issuance and exercise of warrants for purchase of common stock (in shares)

670,312

Common stock, par value (in dollars per share)

$ 0.001

Common stock, shares outstanding (in shares)

7,724,100

2,351,333

2,328,512

Public Stock Offering

Class of Stock [Line Items]

Number of shares sold (in shares)

2,427,500

Proceeds from issuance of common stock and common stock warrants

$ 15,400,000

Legal, accounting and other professional fees

$ 700,000

Over-Allotment Option

Class of Stock [Line Items]

Number of shares sold (in shares)

412,500

Pursuant to Partial Exercise

Class of Stock [Line Items]

Number of shares sold (in shares)

562,500

Securities Purchase Agreement

Class of Stock [Line Items]

Number of shares sold (in shares)

500,000

Sale of stock, price per share (in dollars per share)

$ 6

Common stock, par value (in dollars per share)

$ 0.001

Legal, accounting and other professional fees

$ 400,000

Aggregate gross proceeds for sale of shares

$ 3,000,000

Pre-Funded Warrants | Public Stock Offering

Class of Stock [Line Items]

Sale of stock, price per share (in dollars per share)

$ 3.999

Firm Warrants | Public Stock Offering

Class of Stock [Line Items]

Sale of stock, price per share (in dollars per share)

Exercise price (in dollars per share)

4.40

Representative Warrants | Public Stock Offering

Class of Stock [Line Items]

Shares of common stock to be purchased (in shares)

37,500

Exercise price (in dollars per share)

$ 5

Maximum | Pre-Funded Warrants | Public Stock Offering

Class of Stock [Line Items]

Shares of common stock to be purchased (in shares)

1,735,000

Maximum | Firm Warrants | Public Stock Offering

Class of Stock [Line Items]

Shares of common stock to be purchased (in shares)

3,234,375

Maximum | Firm Warrants | Over-Allotment Option

Class of Stock [Line Items]

Shares of common stock to be purchased (in shares)

421,875

Canaccord Genuity, LLC | Equity Distribution Agreement

Class of Stock [Line Items]

Number of shares sold (in shares)

377,615

Legal, accounting and other professional fees

$ 200,000

Aggregate gross proceeds for sale of shares

$ 2,800,000

Maximum purchase commitment

$ 10,000,000

Commission percentage of gross proceeds from sales of common stock

3.00%

Public float, minimum required amount

$ 75,000,000

Lincoln Park Capital Fund, LLC | Registration Rights Agreement

Class of Stock [Line Items]

Number of shares sold (in shares)

356,122

Legal, accounting and other professional fees

800,000

Aggregate gross proceeds for sale of shares

$ 4,200,000

Maximum purchase commitment

$ 20,000,000

Sale of stock, selling period

36 months

Sale of stock, maximum purchase amount

$ 1,000,000

Sale of stock, maximum number of shares to be issued (in shares)

465,470

Sale of stock, maximum ownership percentage of outstanding shares

9.99%

Sale Of Stock, Tranche One | Lincoln Park Capital Fund, LLC | Registration Rights Agreement

Class of Stock [Line Items]

Sale of stock, minimum price per share (in dollars per share)

$ 0.50

Sale of stock, maximum purchase amount of shares (in shares)

50,000

Sale Of Stock, Tranche Two | Lincoln Park Capital Fund, LLC | Registration Rights Agreement

Class of Stock [Line Items]

Sale of stock, minimum price per share (in dollars per share)

$ 2

Sale of stock, maximum purchase amount of shares (in shares)

100,000

Sale Of Stock, Tranche Three | Lincoln Park Capital Fund, LLC | Registration Rights Agreement

Class of Stock [Line Items]

Sale of stock, minimum price per share (in dollars per share)

$ 3

Sale of stock, maximum purchase amount of shares (in shares)

125,000

Sale Of Stock, Tranche Four | Lincoln Park Capital Fund, LLC | Registration Rights Agreement

Class of Stock [Line Items]

Sale of stock, minimum price per share (in dollars per share)

$ 4

Sale of stock, maximum purchase amount of shares (in shares)

150,000

Subsequent Event | Lincoln Park Capital Fund, LLC | Registration Rights Agreement

Class of Stock [Line Items]

Common stock, par value (in dollars per share)

$ 0.001

Maximum purchase commitment

$ 15,000,000

Sale of stock, selling period

36 months

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2019	Oct. 05, 2016
Class of Stock [Line Items]
Total common stock (in shares)	3,925,774
2016 Equity Incentive Plan
Class of Stock [Line Items]
Total common stock (in shares)	5,337
2016 Employee Stock Purchase Plan
Class of Stock [Line Items]
Total common stock (in shares)	74,520	74,520
Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Total common stock (in shares)	55,574
Stock options issued and outstanding
Class of Stock [Line Items]
Total common stock (in shares)	518,468
Warrant
Class of Stock [Line Items]
Total common stock (in shares)	3,271,875

Income Taxes - Income Tax Provi

Income Taxes - Income Tax Provision (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 0	$ 0
State	14	11
Total current provision	14	11
Deferred:
Federal	0	0
State	0	0
Total deferred provision	0	0
Income tax provision	$ 14	$ 11

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Federal provision (benefit)
At statutory rates	$ (4,971)	$ (7,848)
Change in valuation allowance	4,985	7,859
Income tax provision	$ 14	$ 11

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating losses	$ 35,252	$ 28,708
Tax credits	5,493	4,898
Capitalized research and development costs	2,401	2,566
Other	2,724	2,458
Total gross deferred tax assets	45,870	38,630
Less valuation allowance	(45,578)	(38,630)
Total deferred tax assets	292	0
Deferred tax liabilities:
Other	(292)	0
Total deferred tax liabilities	$ (292)	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
Income Taxes - Additional Information (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 45,578,000	$ 38,630,000
Loss from operations	23,230,000	36,965,000
Unrecognized tax benefits	4,250,000	$ 3,609,000	$ 2,128,000
Unrecognized tax benefits that would impact effective tax rate	0
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	147,900,000
Loss from operations	59,700,000
Federal \| Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward amount	3,400,000
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	114,600,000
State \| Research Tax Credit Carryforward \| California
Operating Loss Carryforwards [Line Items]
Tax credit carryforward amount	$ 2,700,000

Income Taxes - Roll Forward of

Income Taxes - Roll Forward of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	$ 3,609	$ 2,128
Additions based on tax positions related to current year	643	1,513
Additions based on tax positions related to prior years	0	0
Reductions for tax positions related to prior years	(2)	(32)
Balance at December 31	$ 4,250	$ 3,609

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Operating lease, discount rate	7.00%
Rent expense	$ 0.6
Rent expense		$ 0.4
Operating lease payments	0.5
Remaining minimum amount committed	$ 0.5
Minimum
Loss Contingencies [Line Items]
Operating lease, remaining lease term	1 year 7 months 6 days
Maximum
Loss Contingencies [Line Items]
Operating lease, remaining lease term	2 years 3 months 18 days

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Future Noncancelable Minimum Payment Obligations (Details) $ in Thousands	Dec. 31, 2019USD ($)
Operating leases:
2020	$ 537
2021	517
2022	117
Total undiscounted lease payments - operating leases	1,171
Finance leases:
2020	24
2021	24
Total undiscounted lease payments - finance leases	48
Total undiscounted lease payments	1,219
Less: imputed interest	(91)
Lease liability	1,128
Less: current portion of lease liability	(561)
Lease liability, less current portion	$ 567

Variable Interest Entity (Detai

Variable Interest Entity (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Variable Interest Entity [Line Items]
Deferred revenue	$ 424	$ 352
Prepaid Expenses and Other Current Assets
Variable Interest Entity [Line Items]
Deferred revenue	$ 200

Restructuring Charges - Additio

Restructuring Charges - Additional Information (Details) $ in Thousands	Apr. 02, 2019employee	Jun. 30, 2019USD ($)	Apr. 30, 2019USD ($)	Jun. 30, 2019	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges					$ 0	$ 0	$ 1,100	$ 1,099
Number of employees terminated \| employee	49
Percent of workforce terminated	50.00%
Payments for restructuring								819
2019 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Reversal of share-based compensation expense			$ 800
Stock-based compensation expense		$ 700
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges			500					1,008
Asset Disposals
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 100					91
Special Termination Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 600
Consulting agreement term				12 months
Payments for restructuring								$ 300

Restructuring Charges - Restruc

Restructuring Charges - Restructuring and Related Costs (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended			12 Months Ended
	Apr. 30, 2019	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 0	$ 0	$ 1,100	$ 1,099
Employee separation costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 500				1,008
Asset disposals
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 100				$ 91

Restructuring Charges - Restr_2

Restructuring Charges - Restructuring Charges (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0	$ 0	$ 1,100	$ 1,099
Cost of revenue
Restructuring Cost and Reserve [Line Items]
Restructuring charges				53
Research and development
Restructuring Cost and Reserve [Line Items]
Restructuring charges				370
Selling, general and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring charges				$ 676

Restructuring Charges - Restr_3

Restructuring Charges - Restructuring Charge Reserve Balance (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Restructuring Reserve [Roll Forward]
Reserve balance at December 31, 2018	$ 0
Restructuring charges	1,099
Cash payments	(819)
Reserve balance at December 31, 2019	$ 280

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 05, 2020	Jan. 24, 2020	Dec. 27, 2018	Dec. 31, 2019	Feb. 29, 2020	Jan. 13, 2020	Dec. 31, 2018
Subsequent Event [Line Items]
Common stock, par value (in dollars per share)				$ 0.001			$ 0.001
Subsequent Event
Subsequent Event [Line Items]
Lease term		62 months				64 months
Registration Rights Agreement \| Lincoln Park Capital Fund, LLC
Subsequent Event [Line Items]
Maximum purchase commitment			$ 20
Sale of stock, selling period			36 months
Registration Rights Agreement \| Lincoln Park Capital Fund, LLC \| Subsequent Event
Subsequent Event [Line Items]
Maximum purchase commitment	$ 15				$ 15
Common stock, par value (in dollars per share)	$ 0.001
Sale of stock, selling period	36 months
Restricted Stock Units (RSUs)
Subsequent Event [Line Items]
RSUs granted to certain executives (in shares)				55,574
Restricted Stock Units (RSUs) \| Subsequent Event
Subsequent Event [Line Items]
RSUs granted to certain executives (in shares)		816,081