Energy Recovery (ERII) 10-Q1 May 242024 Q1 Quarterly reportFinancial data

Company Profile

Cover Page

Cover Page - shares	3 Months Ended
Cover Page - shares	Mar. 31, 2024	Apr. 25, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-34112
Entity Registrant Name	Energy Recovery, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	01-0616867
Entity Address, Address Line One	1717 Doolittle Drive
Entity Address, City or Town	San Leandro
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94577
City Area Code	510
Local Phone Number	483-7370
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	ERII
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		57,330,153
Entity Central Index Key	0001421517
Document Fiscal Year Focus	2024
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q1
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 70,781	$ 68,098
Short-term investments	46,577	40,445
Accounts receivable, net	25,055	46,937
Inventories, net	31,671	26,149
Prepaid expenses and other assets	4,288	3,843
Total current assets	178,372	185,472
Long-term investments	12,137	13,832
Deferred tax assets, net	11,652	10,324
Property and equipment, net	17,889	18,699
Operating lease, right of use asset	11,038	11,469
Goodwill	12,790	12,790
Other assets, non-current	387	388
Total assets	244,265	252,974
Current liabilities:
Accounts payable	3,492	3,000
Accrued expenses and other liabilities	8,342	15,583
Lease liabilities	1,854	1,791
Contract liabilities	3,449	1,097
Total current liabilities	17,137	21,471
Lease liabilities, non-current	10,959	11,488
Other liabilities, non-current	132	207
Total liabilities	28,228	33,166
Commitments and contingencies (Note 7)
Stockholders’ equity:
Common stock	65	65
Additional paid-in capital	222,122	217,617
Accumulated other comprehensive loss	(60)	(44)
Treasury stock	(80,486)	(80,486)
Retained earnings	74,396	82,656
Total stockholders’ equity	216,037	219,808
Total liabilities and stockholders’ equity	$ 244,265	$ 252,974

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenue	$ 12,090	$ 13,401
Cost of revenue	4,955	5,246
Gross profit	7,135	8,155
Operating expenses:
General and administrative	7,566	7,066
Sales and marketing	6,152	4,894
Research and development	4,351	4,306
Total operating expenses	18,069	16,266
Loss from operations	(10,934)	(8,111)
Other income (expense):
Interest income	1,442	621
Other non-operating income (expense), net	(53)	35
Total other income, net	1,389	656
Loss before income taxes	(9,545)	(7,455)
Benefit from income taxes	(1,285)	(1,159)
Net loss	$ (8,260)	$ (6,296)
Net loss per share:
Basic (in dollars per share)	$ (0.14)	$ (0.11)
Diluted (in dollars per share)	$ (0.14)	$ (0.11)
Number of shares used in per share calculations:
Basic (in shares)	57,102	56,228
Diluted (in shares)	57,102	56,228

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net loss	$ (8,260)	$ (6,296)
Other comprehensive income (loss), net of tax
Foreign currency translation adjustments	28	(17)
Unrealized gain (loss) on investments	(44)	95
Total other comprehensive income (loss), net of tax	(16)	78
Comprehensive loss	$ (8,276)	$ (6,218)

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive loss	Treasury stock	Retained earnings
Beginning balance at Dec. 31, 2022		$ 64	$ 204,957	$ (349)	$ (80,486)	$ 61,152
Beginning balance (in shares) at Dec. 31, 2022		64,225,391
Beginning balance, treasury stock (in shares) at Dec. 31, 2022					8,148,512
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, net			165
Issuance of common stock, net (in shares)		265,993
Stock-based compensation			2,218
Foreign currency translation adjustments				(17)
Unrealized (loss) gain on investments				95
Total other comprehensive income (loss), net of tax	$ 78			78
Net loss	(6,296)					(6,296)
Ending balance, treasury stock (in shares) at Mar. 31, 2023					8,148,512
Ending balance at Mar. 31, 2023	$ 181,503	$ 64	207,340	(271)	$ (80,486)	54,856
Ending balance (in shares) at Mar. 31, 2023	56,342,872	64,491,384
Beginning balance at Dec. 31, 2023	$ 219,808	$ 65	217,617	(44)	$ (80,486)	82,656
Beginning balance (in shares) at Dec. 31, 2023		65,029,459
Beginning balance, treasury stock (in shares) at Dec. 31, 2023					8,148,512
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, net			1,190
Issuance of common stock, net (in shares)		448,455
Stock-based compensation			3,315
Foreign currency translation adjustments				28
Unrealized (loss) gain on investments				(44)
Total other comprehensive income (loss), net of tax	(16)			(16)
Net loss	(8,260)					(8,260)
Ending balance, treasury stock (in shares) at Mar. 31, 2024					8,148,512
Ending balance at Mar. 31, 2024	$ 216,037	$ 65	$ 222,122	$ (60)	$ (80,486)	$ 74,396
Ending balance (in shares) at Mar. 31, 2024	57,329,402	65,477,914

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net loss	$ (8,260)	$ (6,296)
Adjustments to reconcile net loss to cash provided by operating activities
Stock-based compensation	3,283	2,302
Depreciation and amortization	1,029	983
Right of use asset amortization	431	402
Accretion (amortization) of discounts (premiums) on investments	(231)	(89)
Deferred income taxes	(1,328)	(1,152)
Other non-cash adjustments	116	93
Changes in operating assets and liabilities:
Accounts receivable, net	21,882	22,509
Contract assets	0	593
Inventories, net	(5,723)	(4,855)
Prepaid and other assets	(545)	187
Accounts payable	1,140	920
Accrued expenses and other liabilities	(7,589)	(7,156)
Contract liabilities	2,292	216
Net cash provided by operating activities	6,497	8,657
Cash flows from investing activities:
Maturities of marketable securities	16,534	15,250
Purchases of marketable securities	(20,783)	(13,886)
Capital expenditures	(824)	(279)
Proceeds from sales of fixed assets	87	82
Net cash (used in) provided by investing activities	(4,986)	1,167
Cash flows from financing activities:
Net proceeds from issuance of common stock	1,190	165
Net cash provided by financing activities	1,190	165
Effect of exchange rate differences on cash and cash equivalents	(19)	8
Net change in cash, cash equivalents and restricted cash	2,682	9,997
Cash, cash equivalents and restricted cash, beginning of year	68,225	56,458
Cash, cash equivalents and restricted cash, end of period	$ 70,907	$ 66,455

Description of Business and Sig

Description of Business and Significant Accounting Policies	3 Months Ended
Description of Business and Significant Accounting Policies	Mar. 31, 2024
Accounting Policies [Abstract]
Description of Business and Significant Accounting Policies	Description of Business and Significant Accounting Policies Energy Recovery, Inc. and its wholly-owned subsidiaries (the “Company” or “Energy Recovery”) designs and manufactures reliable, high-performance solutions that provide cost savings through improved energy efficiency in commercial and industrial processes, with applications across several industries . Leveraging the Company’s pressure exchanger technology, which generates little to no emissions when operating , the Company believes its solutions lower costs, save energy, reduce waste, and minimize emissions f or companies across a variety of commercial and industrial processes . As the world coalesces around the urgent need to address climate change and its impacts, the Company is helping companies reduce their energy consumption in their industrial processes, which in turn, reduces their carbon footprint. The Company believes that its customers do not have to sacrifice quality and cost savings for sustainability and the Company is committed to developing solutions that drive long-term value – both financial and environmental . The Company’s solutions are marketed, sold in, and developed for, the fluid-flow and gas markets, such as seawater and wastewater desalination, natural gas, chemical processing and CO 2 -based refrigeration systems, under the trademarks ERI ® , PX ® , Pressure Exchanger ® , PX ® Pressure Exchanger ® (“PX”), Ultra PX ™ , PX G ™ , PX G1300 ™ , PX PowerTrain ™ , AT ™ , and Aquabold ™ . The Company owns, manufactures and/or develops its solutions, in whole or in part, in the United States of America (the “U.S.”) . Basis of Presentation The Condensed Consolidated Financial Statements include the accounts of Energy Recovery, Inc. and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The accompanying Condensed Consolidated Financial Statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “ SEC ”). Certain information and footnote disclosures normally included in the financial statements prepared in accordance with U.S. generally accepted accounting principles (“ GAAP ”) have been condensed or omitted pursuant to such rules and regulations. The December 31, 2023 Condensed Consolidated Balance Sheet was derived from audited financial statements and may not include all disclosures required by GAAP; however, the Company believes that the disclosures are adequate to make the information presented not misleading. The March 31, 2024 unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements and the notes thereto for the fiscal year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K filed with the SEC on February 21, 2024 (the “ 2023 Annual Report ”). All adjustments consisting of normal recurring adjustments that are necessary to present fairly the financial position, results of operations and cash flows for the interim periods have been made. The results of operations for the interim periods are not necessarily indicative of the operating results for the full fiscal year or any future periods Use of Estimates The preparation of Condensed Consolidated Financial Statements, in conformity with GAAP , requires the Company’s management to make judgments, assumptions and estimates that affect the amounts reported in the Condensed Consolidated Financial Statements and accompanying notes. The accounting policies that reflect the Company’s significant estimates and judgments and that the Company believes are the most critical to aid in fully understanding and evaluating its reported financial results are revenue recognition; granted equity award valuations; equipment useful life and valuation; goodwill valuation and impairment; deferred taxes and valuation allowances on deferred tax assets; and evaluation and measurement of contingencies . Those estimates could change, and as a result, actual results could differ materially from those estimates. The Company is not aware of any specific event or circumstance that would require an update to its estimates or judgments or a revision of the carrying value of its assets or liabilities as of May 1, 2024 , the date of issuance of this Quarterly Report on Form 10-Q . These estimates may change, as new events occur and additional information is obtained. Actual results could differ materially from these estimates under different assumptions or conditions. The Company undertakes no obligation to publicly update these estimates for any reason after the date of this Quarterly Report on Form 10-Q , except as required by law. Significant Accounting Policies There have been no material changes to the Company’s significant accounting policies in Note 1, “ Description of Business and Significant Accounting Policies - Significant Accounting Policies ,” of the 2023 Annual Report . Recently Issued Accounting Pronouncement Not Yet Adopted There have been no issued accounting pronouncements that have not yet been adopted during the three months ended March 31, 2024 that apply to the Company other than the pronouncements disclosed in Note 1, “ Description of Business and Significant Accounting Policies - Recently Issued Accounting Pronouncement Not Yet Adopted ,” of the 2023 Annual Report .

Revenue

Revenue	3 Months Ended
Revenue	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue	Revenue Disaggregation of Revenue The following table present s the disaggregated revenues by segment, and within each segment, by geographical market based on the customer “shipped to” address, and by channel customers. Sales and usage-based taxes are excluded from revenues. See Note 9 , “ Segment Reporting ,” for further discussion related to the Company’s segments. Three Months Ended March 31, 2024 Three Months Ended March 31, 2023 Water Emerging Technologies Total Water Emerging Technologies Total (In thousands) Geographical market Middle East and Africa $ 4,785 $ 1 $ 4,786 $ 2,739 $ — $ 2,739 Americas 3,939 — 3,939 3,208 30 3,238 Asia 1,979 — 1,979 6,114 — 6,114 Europe 1,386 — 1,386 1,235 75 1,310 Total revenue $ 12,089 $ 1 $ 12,090 $ 13,296 $ 105 $ 13,401 Channel Aftermarket $ 4,643 $ 1 $ 4,644 $ 3,322 $ — $ 3,322 Megaproject 4,100 — 4,100 3,243 — 3,243 Original equipment manufacturer 3,346 — 3,346 6,731 105 6,836 Total revenue $ 12,089 $ 1 $ 12,090 $ 13,296 $ 105 $ 13,401 Contract Balances The following table presents contract balances by category. March 31, 2024 December 31, 2023 (In thousands) Accounts receivable, net $ 25,055 $ 46,937 Contract assets, current (included in prepaid expenses and other assets) 592 592 Contract liabilities: Contract liabilities, current $ 3,449 $ 1,097 Contract liabilities, non-current (included in other liabilities, non-current) 30 90 Total contract liabilities $ 3,479 $ 1,187 Contract Liabilities The Company records contract liabilities, which consist of customer deposits and deferred revenue, when cash payments are received in advance of the Company’s performance. The following table presents significant changes in contract liabilities during the period. March 31, 2024 December 31, 2023 (In thousands) Contract liabilities, beginning of year $ 1,187 $ 1,316 Revenue recognized (1,038) (1,254) Cash received, excluding amounts recognized as revenue during the period 3,330 1,125 Contract liabilities, end of period $ 3,479 $ 1,187 Remaining Performance Obligations As of March 31, 2024 , t he following table presents the revenue that is expected to be recognized related to performance obligations that are unsatisfied or partially unsatisfied. Period Remaining Performance Obligations (In thousands) 2024 (remaining nine months) $ 6,021 2025 840

Net Loss Per Share

Net Loss Per Share	3 Months Ended
Net Loss Per Share	Mar. 31, 2024
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Net loss for the reported period is divided by the weighted average number of basic and diluted common shares outstanding during the reported period to calculate the basic and diluted net loss per common share , respectively. The following table presents the computation of basic and diluted net loss per common share . Three Months Ended March 31, 2024 2023 (In thousands, except per share amounts) Numerator Net loss $ (8,260) $ (6,296) Denominator (weighted average shares) Basic and dilutive common shares outstanding 57,102 56,228 Net loss per share Basic $ (0.14) $ (0.11) Diluted $ (0.14) $ (0.11) The following table presents the equity awards that are excluded from diluted net loss per share because their effect would have been anti-dilutive. Three Months Ended March 31, 2024 2023 (In thousands) Anti-dilutive equity award shares 3,286 2,652

Other Financial Information

Other Financial Information	3 Months Ended
Other Financial Information	Mar. 31, 2024
Other Financial Information [Abstract]
Other Financial Information	Other Financial Information Cash, Cash Equivalents and Restricted Cash The Condensed Consolidated Statements of Cash Flows explain the changes in the total of cash, cash equivalents and restricted cash, such as cash amounts deposited in restricted cash accounts in connection with the Company’s credit cards. The following table presents a reconciliation of cash, cash equivalents and restricted cash, reported for each period within the Condensed Consolidated Balance Sheets and the Condensed Consolidated Statements of Cash Flows that sum to the total of such amounts. March 31, 2024 December 31, 2023 March 31, 2023 (In thousands) Cash and cash equivalents $ 70,781 $ 68,098 $ 66,332 Restricted cash, non-current (included in other assets, non-current) 126 127 123 Total cash, cash equivalents and restricted cash $ 70,907 $ 68,225 $ 66,455 Accounts Receivable, net March 31, 2024 December 31, 2023 (In thousands) Accounts receivable, gross $ 25,193 $ 47,075 Allowance for doubtful accounts (138) (138) Accounts receivable, net $ 25,055 $ 46,937 Inventories, net Inventory amounts are stated at the lower of cost or net realizable value, using the first-in, first-out method. March 31, 2024 December 31, 2023 (In thousands) Raw materials $ 8,883 $ 8,752 Work in process 7,507 5,234 Finished goods 16,579 13,319 Inventories, gross 32,969 27,305 Valuation adjustments for excess and obsolete inventory (1,298) (1,156) Inventories, net $ 31,671 $ 26,149 Accrued Expenses and Other Liabilities March 31, 2024 December 31, 2023 (In thousands) Current Payroll, incentives and commissions payable $ 4,577 $ 11,037 Warranty reserve 989 1,057 Income taxes payable 1,083 1,077 Other accrued expenses and other liabilities 1,693 2,412 Total accrued expenses and other liabilities 8,342 15,583 Other liabilities, non-current 132 207 Total accrued expenses, and current and non-current other liabilities $ 8,474 $ 15,790

Investments and Fair Value Meas

Investments and Fair Value Measurements	3 Months Ended
Investments and Fair Value Measurements	Mar. 31, 2024
Investments, Fair Value Disclosure [Abstract]
Investments and Fair Value Measurements	Investments and Fair Value Measurements Fair Value of Financial Instruments The following table presents the Company’s financial assets measured on a recurring basis by contractual maturity, including pricing category, amortized cost, gross unrealized gains and losses, and fair value. As of the dates reported in the table, the Company had no financial liabilities and no Level 3 financial assets. March 31, 2024 December 31, 2023 Pricing Category Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (In thousands) Cash equivalents Money market securities Level 1 $ 25,233 $ — $ — $ 25,233 $ 18,767 $ — $ — $ 18,767 Short-term investments U.S. treasury securities Level 2 6,406 — (3) 6,403 4,900 1 (1) 4,900 Corporate notes and bonds Level 2 33,246 1 (40) 33,207 25,674 11 (18) 25,667 Municipal and agency notes and bonds Level 2 6,971 — (4) 6,967 9,887 — (9) 9,878 Total short-term investments 46,623 1 (47) 46,577 40,461 12 (28) 40,445 Long-term investments Corporate notes and bonds Level 2 8,048 2 (5) 8,045 9,229 28 (3) 9,254 Municipal and agency notes and bonds Level 2 4,098 — (6) 4,092 4,585 — (7) 4,578 Total long-term investments 12,146 2 (11) 12,137 13,814 28 (10) 13,832 Total short and long-term investments 58,769 3 (58) 58,714 54,275 40 (38) 54,277 Total $ 84,002 $ 3 $ (58) $ 83,947 $ 73,042 $ 40 $ (38) $ 73,044 The following table presents a summary of the fair value and gross unrealized losses on the available-for-sale securities that have been in a continuous unrealized loss position, aggregated by type of investment instrument. The available-for-sale securities that were in an unrealized gain position have been excluded from the table. March 31, 2024 December 31, 2023 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses (In thousands) U.S. treasury securities $ 5,406 $ (3) $ 2,931 $ (1) Corporate notes and bonds 37,568 (45) 15,276 (21) Municipal and agency notes and bonds 9,060 (10) 12,956 (16) Total available-for-sale investments with unrealized loss positions $ 52,034 $ (58) $ 31,163 $ (38)

Lines of Credit

Lines of Credit	3 Months Ended
Lines of Credit	Mar. 31, 2024
Debt Disclosure [Abstract]
Lines of Credit	Lines of Credit Credit Agreement The Company entered into a credit agreement with JPMorgan Chase Bank, N.A. (“ JPMC ”) on December 22, 2021 (as amended, the “ Credit Agreement ”). The Credit Agreement , which will expire on December 21, 2026 , provides a committed revolving credit line of $50.0 million and includes both a revolving loan and a letters of credit (“ LCs ”) component. Under the Credit Agreement , as of March 31, 2024 , there were no revolving loans outstanding. In addition, under the LCs component, the Company utilized $20.3 million of the maximum allowable credit line of $30.0 million , which includes newly issued LCs , and previously issued and unexpired stand-by letters of credit (“SBLCs”) and certain non-expired commitments under the Company’s previous Loan and Pledge Agreement with Citibank, N.A. which are guaranteed under the Credit Agreement . Letters of Credit The following table presents the total outstanding LCs and SBLCs issued by the Company to its customers related to product warranty and performance guarantees . March 31, 2024 December 31, 2023 (In thousands) Outstanding letters of credit $ 18,293 $ 19,945

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation From time-to-time, the Company has been named in and subject to various proceedings and claims in connection with its business. The Company may in the future become involved in litigation in the ordinary course of business, including litigation that could be material to its business. The Company considers all claims, if any, on a quarterly basis and, based on known facts, assesses whether potential losses are considered reasonably possible, probable and estimable. Based upon this assessment, the Company then evaluates disclosure requirements and whether to accrue for such claims in its consolidated financial statements. The Company records a provision for a liability when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. These provisions are reviewed at least quarterly and are adjusted to reflect the impacts of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular case. As of March 31, 2024 , the Company was not involved in any lawsuits, legal proceedings or claims that would have a material effect on the Company’s financial position, results of operations, or cash flows. Therefore, there were no material losses which were probable or reasonably possible.

Income Taxes

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Three Months Ended March 31, 2024 2023 (In thousands, except percentages) Benefit from income taxes $ (1,285) $ (1,159) Discrete items 76 488 Benefit from income taxes, excluding discrete items $ (1,209) $ (671) Effective tax rate 13.5% 15.5% Effective tax rate, excluding discrete items 12.7% 9.0% The Company’s interim period tax benefit from income taxes is determined using an estimate of its annual effective tax rate, adjusted for discrete items, if any, that arise during the period . Each quarter, the Company update s its estimate of the annual effective tax rate, and if the estimated annual effective tax rate changes, the Company makes a cumulative adjustment in such period . The Company’s quarterly tax provision and estimate of its annual effective tax rate are subject to variation due to several factors, including variability in accurately predicting its pre-tax income or loss and the mix of jurisdictions to which they relate, intercompany transactions, the applicability of special tax regimes, and changes in how the Company does business . For the three months ended March 31, 2024 , the recognized benefit from income taxes resulted from the loss for the quarter and i ncluded benefits related to the U.S. federal foreign-derived intangible income (“FDII”) and federal research and development (“ R&D ”) tax credit , partially offset by certain permanent differences, such as share-based compensation . For the three months ended March 31, 2023, the recognized benefit from income tax resulted from the loss for the quarter and included benefits related to the U.S. FDII and federal R&D tax credit, along with a discrete tax benefit due primarily to share-based compensation windfalls. The effective tax rate excluding discrete items for the three months ended March 31, 2024 , as compared to the prior year, differed primarily due to lower projected U.S. FDII and federal R&D tax credits and higher book income, as well as non-deductible officer share-based compensation and certain foreign-based employee share-based compensation .

Segment Reporting

Segment Reporting	3 Months Ended
Segment Reporting	Mar. 31, 2024
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting The Company’s Chief Operating Decision-Maker (“CODM”) is its chief executive officer. The Company continue s to monitor and review its segment reporting structure in accordance with authoritative guidance to determine whether any changes have occurred that would impact its reportable segments . The following table presents a summary of the Company’s financial information by segment and corporate operating expenses. Three Months Ended March 31, 2024 2023 Water Emerging Technologies Total Water Emerging Technologies Total (In thousands) Revenue $ 12,089 $ 1 $ 12,090 $ 13,296 $ 105 $ 13,401 Cost of revenue 4,954 1 4,955 5,101 145 5,246 Gross profit (loss) 7,135 — 7,135 8,195 (40) 8,155 Operating expenses General and administrative 1,922 1,018 2,940 1,938 968 2,906 Sales and marketing 3,745 1,807 5,552 3,175 1,170 4,345 Research and development 1,100 3,251 4,351 1,180 3,126 4,306 Total operating expenses 6,767 6,076 12,843 6,293 5,264 11,557 Operating income (loss) $ 368 $ (6,076) (5,708) $ 1,902 $ (5,304) (3,402) Less: Corporate operating expenses 5,226 4,709 Loss from operations $ (10,934) $ (8,111)

Concentrations

Concentrations	3 Months Ended
Concentrations	Mar. 31, 2024
Risks and Uncertainties [Abstract]
Concentrations	Concentrations Customer Revenue Concentration The following table presents the customers that account for 10% or more of the Company’s revenue and their related segment for each of the periods presented. Although certain customers might account for greater than 10% of the Company’s revenue at any one point in time, the concentration of revenue between a limited number of customers shifts regularly, depending on when revenue is recognized. The percentages by customer reflect specific relationships or contracts that would concentrate revenue for the periods presented and do not indicate a trend specific to any one customer. Three Months Ended March 31, Segment 2024 2023 Customer A Water 27% Customer B Water 18% Customer C Water 13% Customer D Water 11% ** Zero or less than 10%.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net loss	$ (8,260)	$ (6,296)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Name Title Date of Adoption or Termination (1) Status (2) Plan Type Joshua Ballard Chief Financial Officer January 3, 2024 Termination Rule 10b5-1 trading arrangement (3) Arve Hanstveit Director March 15, 2024 Termination Rule 10b5-1 trading arrangement (4) (1) Effective (a) date of adoption; or (b) date of termination, of registrant’s Rule 10b5-1 trading arrangement. (2) Activity related to registrant’s Rule 10b5-1 trading arrangement. (3) The trading arrangement covered the sale of up to 12,500 shares of our common stock and was scheduled to expire on September 13, 2024 or upon the completion of all sales thereunder. (4) The trading arrangement covered the sale of up to 76,000 shares of our common stock and was scheduled to expire on March 15, 2024 or upon the completion of all sales thereunder.
Joshua Ballard [Member]
Trading Arrangements, by Individual
Name	Joshua Ballard
Title	Chief Financial Officer
Rule 10b5-1 Arrangement Terminated	true
Termination Date	January 3, 2024
Aggregate Available	12,500
Arve Hanstveit [Member]
Trading Arrangements, by Individual
Name	Arve Hanstveit
Title	Director
Rule 10b5-1 Arrangement Terminated	true
Termination Date	March 15, 2024
Aggregate Available	76,000

Description of Business and S_2

Description of Business and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	The Condensed Consolidated Financial Statements include the accounts of Energy Recovery, Inc. and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. The accompanying Condensed Consolidated Financial Statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (the “ SEC ”). Certain information and footnote disclosures normally included in the financial statements prepared in accordance with U.S. generally accepted accounting principles (“ GAAP ”) have been condensed or omitted pursuant to such rules and regulations. All adjustments consisting of normal recurring adjustments that are necessary to present fairly the financial position, results of operations and cash flows for the interim periods have been made. The results of operations for the interim periods are not necessarily indicative of the operating results for the full fiscal year or any future periods .
Use of Estimates	The preparation of Condensed Consolidated Financial Statements, in conformity with GAAP , requires the Company’s management to make judgments, assumptions and estimates that affect the amounts reported in the Condensed Consolidated Financial Statements and accompanying notes. The accounting policies that reflect the Company’s significant estimates and judgments and that the Company believes are the most critical to aid in fully understanding and evaluating its reported financial results are revenue recognition; granted equity award valuations; equipment useful life and valuation; goodwill valuation and impairment; deferred taxes and valuation allowances on deferred tax assets; and evaluation and measurement of contingencies . Those estimates could change, and as a result, actual results could differ materially from those estimates. The Company is not aware of any specific event or circumstance that would require an update to its estimates or judgments or a revision of the carrying value of its assets or liabilities as of May 1, 2024 , the date of issuance of this Quarterly Report on Form 10-Q . These estimates may change, as new events occur and additional information is obtained. Actual results could differ materially from these estimates under different assumptions or conditions. The Company undertakes no obligation to publicly update these estimates for any reason after the date of this Quarterly Report on Form 10-Q , except as required by law.
Litigation	The Company considers all claims, if any, on a quarterly basis and, based on known facts, assesses whether potential losses are considered reasonably possible, probable and estimable. Based upon this assessment, the Company then evaluates disclosure requirements and whether to accrue for such claims in its consolidated financial statements. The Company records a provision for a liability when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. These provisions are reviewed at least quarterly and are adjusted to reflect the impacts of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular case.
Income Taxes	The Company’s interim period tax benefit from income taxes is determined using an estimate of its annual effective tax rate, adjusted for discrete items, if any, that arise during the period . Each quarter, the Company update s its estimate of the annual effective tax rate, and if the estimated annual effective tax rate changes, the Company makes a cumulative adjustment in such period . The Company’s quarterly tax provision and estimate of its annual effective tax rate are subject to variation due to several factors, including variability in accurately predicting its pre-tax income or loss and the mix of jurisdictions to which they relate, intercompany transactions, the applicability of special tax regimes, and changes in how the Company does business .

Revenue (Tables)

Revenue (Tables)	3 Months Ended
Revenue (Tables)	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table present s the disaggregated revenues by segment, and within each segment, by geographical market based on the customer “shipped to” address, and by channel customers. Sales and usage-based taxes are excluded from revenues. See Note 9 , “ Segment Reporting ,” for further discussion related to the Company’s segments. Three Months Ended March 31, 2024 Three Months Ended March 31, 2023 Water Emerging Technologies Total Water Emerging Technologies Total (In thousands) Geographical market Middle East and Africa $ 4,785 $ 1 $ 4,786 $ 2,739 $ — $ 2,739 Americas 3,939 — 3,939 3,208 30 3,238 Asia 1,979 — 1,979 6,114 — 6,114 Europe 1,386 — 1,386 1,235 75 1,310 Total revenue $ 12,089 $ 1 $ 12,090 $ 13,296 $ 105 $ 13,401 Channel Aftermarket $ 4,643 $ 1 $ 4,644 $ 3,322 $ — $ 3,322 Megaproject 4,100 — 4,100 3,243 — 3,243 Original equipment manufacturer 3,346 — 3,346 6,731 105 6,836 Total revenue $ 12,089 $ 1 $ 12,090 $ 13,296 $ 105 $ 13,401
Schedule of Contract with Customer, Asset and Liability	The following table presents contract balances by category. March 31, 2024 December 31, 2023 (In thousands) Accounts receivable, net $ 25,055 $ 46,937 Contract assets, current (included in prepaid expenses and other assets) 592 592 Contract liabilities: Contract liabilities, current $ 3,449 $ 1,097 Contract liabilities, non-current (included in other liabilities, non-current) 30 90 Total contract liabilities $ 3,479 $ 1,187
Schedule of Contract With Customer, Contract Liability, Activity	The Company records contract liabilities, which consist of customer deposits and deferred revenue, when cash payments are received in advance of the Company’s performance. The following table presents significant changes in contract liabilities during the period. March 31, 2024 December 31, 2023 (In thousands) Contract liabilities, beginning of year $ 1,187 $ 1,316 Revenue recognized (1,038) (1,254) Cash received, excluding amounts recognized as revenue during the period 3,330 1,125 Contract liabilities, end of period $ 3,479 $ 1,187
Schedule of Revenue, Remaining Performance Obligation	As of March 31, 2024 , t he following table presents the revenue that is expected to be recognized related to performance obligations that are unsatisfied or partially unsatisfied. Period Remaining Performance Obligations (In thousands) 2024 (remaining nine months) $ 6,021 2025 840

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
Net Loss Per Share (Tables)	Mar. 31, 2024
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table presents the computation of basic and diluted net loss per common share . Three Months Ended March 31, 2024 2023 (In thousands, except per share amounts) Numerator Net loss $ (8,260) $ (6,296) Denominator (weighted average shares) Basic and dilutive common shares outstanding 57,102 56,228 Net loss per share Basic $ (0.14) $ (0.11) Diluted $ (0.14) $ (0.11)
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table presents the equity awards that are excluded from diluted net loss per share because their effect would have been anti-dilutive. Three Months Ended March 31, 2024 2023 (In thousands) Anti-dilutive equity award shares 3,286 2,652

Other Financial Information (Ta

Other Financial Information (Tables)	3 Months Ended
Other Financial Information (Tables)	Mar. 31, 2024
Other Financial Information [Abstract]
Schedule of Restrictions on Cash and Cash Equivalents	The following table presents a reconciliation of cash, cash equivalents and restricted cash, reported for each period within the Condensed Consolidated Balance Sheets and the Condensed Consolidated Statements of Cash Flows that sum to the total of such amounts. March 31, 2024 December 31, 2023 March 31, 2023 (In thousands) Cash and cash equivalents $ 70,781 $ 68,098 $ 66,332 Restricted cash, non-current (included in other assets, non-current) 126 127 123 Total cash, cash equivalents and restricted cash $ 70,907 $ 68,225 $ 66,455
Schedule of Accounts Receivable, net	March 31, 2024 December 31, 2023 (In thousands) Accounts receivable, gross $ 25,193 $ 47,075 Allowance for doubtful accounts (138) (138) Accounts receivable, net $ 25,055 $ 46,937
Schedule of Inventories, Net	March 31, 2024 December 31, 2023 (In thousands) Raw materials $ 8,883 $ 8,752 Work in process 7,507 5,234 Finished goods 16,579 13,319 Inventories, gross 32,969 27,305 Valuation adjustments for excess and obsolete inventory (1,298) (1,156) Inventories, net $ 31,671 $ 26,149
Schedule of Accrued Expenses and Other Liabilities	March 31, 2024 December 31, 2023 (In thousands) Current Payroll, incentives and commissions payable $ 4,577 $ 11,037 Warranty reserve 989 1,057 Income taxes payable 1,083 1,077 Other accrued expenses and other liabilities 1,693 2,412 Total accrued expenses and other liabilities 8,342 15,583 Other liabilities, non-current 132 207 Total accrued expenses, and current and non-current other liabilities $ 8,474 $ 15,790

Investments and Fair Value Me_2

Investments and Fair Value Measurements (Tables)	3 Months Ended
Investments and Fair Value Measurements (Tables)	Mar. 31, 2024
Investments, Fair Value Disclosure [Abstract]
Schedule of Amortized Cost and Fair Value of Available for Sale Securities	The following table presents the Company’s financial assets measured on a recurring basis by contractual maturity, including pricing category, amortized cost, gross unrealized gains and losses, and fair value. As of the dates reported in the table, the Company had no financial liabilities and no Level 3 financial assets. March 31, 2024 December 31, 2023 Pricing Category Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (In thousands) Cash equivalents Money market securities Level 1 $ 25,233 $ — $ — $ 25,233 $ 18,767 $ — $ — $ 18,767 Short-term investments U.S. treasury securities Level 2 6,406 — (3) 6,403 4,900 1 (1) 4,900 Corporate notes and bonds Level 2 33,246 1 (40) 33,207 25,674 11 (18) 25,667 Municipal and agency notes and bonds Level 2 6,971 — (4) 6,967 9,887 — (9) 9,878 Total short-term investments 46,623 1 (47) 46,577 40,461 12 (28) 40,445 Long-term investments Corporate notes and bonds Level 2 8,048 2 (5) 8,045 9,229 28 (3) 9,254 Municipal and agency notes and bonds Level 2 4,098 — (6) 4,092 4,585 — (7) 4,578 Total long-term investments 12,146 2 (11) 12,137 13,814 28 (10) 13,832 Total short and long-term investments 58,769 3 (58) 58,714 54,275 40 (38) 54,277 Total $ 84,002 $ 3 $ (58) $ 83,947 $ 73,042 $ 40 $ (38) $ 73,044
Schedule of Gross Unrealized Losses and Fair Values of Investments	The following table presents a summary of the fair value and gross unrealized losses on the available-for-sale securities that have been in a continuous unrealized loss position, aggregated by type of investment instrument. The available-for-sale securities that were in an unrealized gain position have been excluded from the table. March 31, 2024 December 31, 2023 Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses (In thousands) U.S. treasury securities $ 5,406 $ (3) $ 2,931 $ (1) Corporate notes and bonds 37,568 (45) 15,276 (21) Municipal and agency notes and bonds 9,060 (10) 12,956 (16) Total available-for-sale investments with unrealized loss positions $ 52,034 $ (58) $ 31,163 $ (38)

Lines of Credit (Tables)

Lines of Credit (Tables)	3 Months Ended
Lines of Credit (Tables)	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Debt	The following table presents the total outstanding LCs and SBLCs issued by the Company to its customers related to product warranty and performance guarantees . March 31, 2024 December 31, 2023 (In thousands) Outstanding letters of credit $ 18,293 $ 19,945

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
Income Taxes (Tables)	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	Three Months Ended March 31, 2024 2023 (In thousands, except percentages) Benefit from income taxes $ (1,285) $ (1,159) Discrete items 76 488 Benefit from income taxes, excluding discrete items $ (1,209) $ (671) Effective tax rate 13.5% 15.5% Effective tax rate, excluding discrete items 12.7% 9.0%

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
Segment Reporting (Tables)	Mar. 31, 2024
Segment Reporting [Abstract]
Schedule of Financial Information by Segment	The following table presents a summary of the Company’s financial information by segment and corporate operating expenses. Three Months Ended March 31, 2024 2023 Water Emerging Technologies Total Water Emerging Technologies Total (In thousands) Revenue $ 12,089 $ 1 $ 12,090 $ 13,296 $ 105 $ 13,401 Cost of revenue 4,954 1 4,955 5,101 145 5,246 Gross profit (loss) 7,135 — 7,135 8,195 (40) 8,155 Operating expenses General and administrative 1,922 1,018 2,940 1,938 968 2,906 Sales and marketing 3,745 1,807 5,552 3,175 1,170 4,345 Research and development 1,100 3,251 4,351 1,180 3,126 4,306 Total operating expenses 6,767 6,076 12,843 6,293 5,264 11,557 Operating income (loss) $ 368 $ (6,076) (5,708) $ 1,902 $ (5,304) (3,402) Less: Corporate operating expenses 5,226 4,709 Loss from operations $ (10,934) $ (8,111)

Concentrations (Tables)

Concentrations (Tables)	3 Months Ended
Concentrations (Tables)	Mar. 31, 2024
Risks and Uncertainties [Abstract]
Schedules of Concentration of Risk, by Risk Factor	The following table presents the customers that account for 10% or more of the Company’s revenue and their related segment for each of the periods presented. Although certain customers might account for greater than 10% of the Company’s revenue at any one point in time, the concentration of revenue between a limited number of customers shifts regularly, depending on when revenue is recognized. The percentages by customer reflect specific relationships or contracts that would concentrate revenue for the periods presented and do not indicate a trend specific to any one customer. Three Months Ended March 31, Segment 2024 2023 Customer A Water 27% Customer B Water 18% Customer C Water 13% Customer D Water 11% ** Zero or less than 10%.

Revenue - Schedule of Disaggreg

Revenue - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 12,090	$ 13,401
Water
Disaggregation of Revenue [Line Items]
Revenue	12,089	13,296
Emerging Technologies
Disaggregation of Revenue [Line Items]
Revenue	1	105
Aftermarket
Disaggregation of Revenue [Line Items]
Revenue	4,644	3,322
Aftermarket \| Water
Disaggregation of Revenue [Line Items]
Revenue	4,643	3,322
Aftermarket \| Emerging Technologies
Disaggregation of Revenue [Line Items]
Revenue	1	0
Megaproject
Disaggregation of Revenue [Line Items]
Revenue	4,100	3,243
Megaproject \| Water
Disaggregation of Revenue [Line Items]
Revenue	4,100	3,243
Megaproject \| Emerging Technologies
Disaggregation of Revenue [Line Items]
Revenue	0	0
Original equipment manufacturer
Disaggregation of Revenue [Line Items]
Revenue	3,346	6,836
Original equipment manufacturer \| Water
Disaggregation of Revenue [Line Items]
Revenue	3,346	6,731
Original equipment manufacturer \| Emerging Technologies
Disaggregation of Revenue [Line Items]
Revenue	0	105
Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenue	4,786	2,739
Middle East and Africa \| Water
Disaggregation of Revenue [Line Items]
Revenue	4,785	2,739
Middle East and Africa \| Emerging Technologies
Disaggregation of Revenue [Line Items]
Revenue	1	0
Americas
Disaggregation of Revenue [Line Items]
Revenue	3,939	3,238
Americas \| Water
Disaggregation of Revenue [Line Items]
Revenue	3,939	3,208
Americas \| Emerging Technologies
Disaggregation of Revenue [Line Items]
Revenue	0	30
Asia
Disaggregation of Revenue [Line Items]
Revenue	1,979	6,114
Asia \| Water
Disaggregation of Revenue [Line Items]
Revenue	1,979	6,114
Asia \| Emerging Technologies
Disaggregation of Revenue [Line Items]
Revenue	0	0
Europe
Disaggregation of Revenue [Line Items]
Revenue	1,386	1,310
Europe \| Water
Disaggregation of Revenue [Line Items]
Revenue	1,386	1,235
Europe \| Emerging Technologies
Disaggregation of Revenue [Line Items]
Revenue	$ 0	$ 75

Revenue - Schedule of Contract

Revenue - Schedule of Contract with Customer, Asset and Liability (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 25,055	$ 46,937
Contract assets, current (included in prepaid expenses and other assets)	592	592
Contract liabilities:
Contract liabilities, current	3,449	1,097
Contract liabilities, non-current (included in other liabilities, non-current)	30	90
Total contract liabilities	$ 3,479	$ 1,187	$ 1,316

Revenue - Schedule of Contrac_2

Revenue - Schedule of Contract With Customer, Contract Liability, Activity (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Contract With Customer, Liability [Roll Forward]
Contract liabilities, beginning of year	$ 1,187	$ 1,316
Revenue recognized	(1,038)	(1,254)
Cash received, excluding amounts recognized as revenue during the period	3,330	1,125
Contract liabilities, end of period	$ 3,479	$ 1,187

Revenue - Schedule of Remaining

Revenue - Schedule of Remaining Performance Obligation (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligations expected to be satisfied	$ 6,021
Performance obligations expected to be satisfied, expected timing	9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligations expected to be satisfied	$ 840
Performance obligations expected to be satisfied, expected timing	1 year

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator
Net loss	$ (8,260)	$ (6,296)
Denominator (weighted average shares)
Basic common shares outstanding (in shares)	57,102	56,228
Diluted common shares outstanding (in shares)	57,102	56,228
Net loss per share
Basic (in dollars per share)	$ (0.14)	$ (0.11)
Diluted (in dollars per share)	$ (0.14)	$ (0.11)

Net Loss Per Share - Schedule_2

Net Loss Per Share - Schedule of Antidilutive Securities Excluded From Computation of Diluted Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Anti-dilutive equity award shares (in shares)	3,286	2,652

Other Financial Information - S

Other Financial Information - Schedule of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Other Financial Information [Abstract]
Cash and cash equivalents	$ 70,781	$ 68,098	$ 66,332
Restricted cash, non-current (included in other assets, non-current)	126	127	123
Total cash, cash equivalents and restricted cash	$ 70,907	$ 68,225	$ 66,455	$ 56,458

Other Financial Information -_2

Other Financial Information - Schedule of Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Other Financial Information [Abstract]
Accounts receivable, gross	$ 25,193	$ 47,075
Allowance for doubtful accounts	(138)	(138)
Accounts receivable, net	$ 25,055	$ 46,937

Other Financial Information -_3

Other Financial Information - Schedule of Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Other Financial Information [Abstract]
Raw materials	$ 8,883	$ 8,752
Work in process	7,507	5,234
Finished goods	16,579	13,319
Inventories, gross	32,969	27,305
Valuation adjustments for excess and obsolete inventory	(1,298)	(1,156)
Inventories, net	$ 31,671	$ 26,149

Other Financial Information -_4

Other Financial Information - Schedule of Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current
Payroll, incentives and commissions payable	$ 4,577	$ 11,037
Warranty reserve	989	1,057
Income taxes payable	1,083	1,077
Other accrued expenses and other liabilities	1,693	2,412
Total accrued expenses and other liabilities	8,342	15,583
Non-current
Other liabilities, non-current	132	207
Total accrued expenses, and current and non-current other liabilities	$ 8,474	$ 15,790

Investments and Fair Value Me_3

Investments and Fair Value Measurements - Schedule of Amortized Cost and Fair Value of Available for Sale Securities (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Amortized cost	$ 84,002,000	$ 73,042,000
Gross unrealized gain	3,000	40,000
Gross unrealized losses	(58,000)	(38,000)
Fair value	83,947,000	73,044,000
Total short and long-term investments
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Amortized cost	58,769,000	54,275,000
Gross unrealized gain	3,000	40,000
Gross unrealized losses	(58,000)	(38,000)
Fair value	58,714,000	54,277,000
Short-term investments
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Amortized cost	46,623,000	40,461,000
Gross unrealized gain	1,000	12,000
Gross unrealized losses	(47,000)	(28,000)
Fair value	46,577,000	40,445,000
Long-term investments
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Amortized cost	12,146,000	13,814,000
Gross unrealized gain	2,000	28,000
Gross unrealized losses	(11,000)	(10,000)
Fair value	12,137,000	13,832,000
Level 1 \| Cash equivalents \| Money market securities
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Amortized cost	25,233,000	18,767,000
Gross unrealized gain	0	0
Gross unrealized losses	0	0
Fair value	25,233,000	18,767,000
Level 2 \| Short-term investments \| U.S. treasury securities
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Amortized cost	6,406,000	4,900,000
Gross unrealized gain	0	1,000
Gross unrealized losses	(3,000)	(1,000)
Fair value	6,403,000	4,900,000
Level 2 \| Short-term investments \| Corporate notes and bonds
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Amortized cost	33,246,000	25,674,000
Gross unrealized gain	1,000	11,000
Gross unrealized losses	(40,000)	(18,000)
Fair value	33,207,000	25,667,000
Level 2 \| Short-term investments \| Municipal and agency notes and bonds
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Amortized cost	6,971,000	9,887,000
Gross unrealized gain	0	0
Gross unrealized losses	(4,000)	(9,000)
Fair value	6,967,000	9,878,000
Level 2 \| Long-term investments \| Corporate notes and bonds
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Amortized cost	8,048,000	9,229,000
Gross unrealized gain	2,000	28,000
Gross unrealized losses	(5,000)	(3,000)
Fair value	8,045,000	9,254,000
Level 2 \| Long-term investments \| Municipal and agency notes and bonds
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Amortized cost	4,098,000	4,585,000
Gross unrealized gain	0	0
Gross unrealized losses	(6,000)	(7,000)
Fair value	4,092,000	4,578,000
Measured On Recurring Basis
Debt Securities, Available-for-sale [Line Items]
Total fair value of financial liabilities	0	0
Measured On Recurring Basis \| Level 3
Debt Securities, Available-for-sale [Line Items]
Total fair value of financial assets	$ 0	$ 0

Investments and Fair Value Me_4

Investments and Fair Value Measurements - Schedule of Gross Unrealized Losses and Fair Values of Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Fair value	$ 52,034	$ 31,163
Gross unrealized losses	(58)	(38)
U.S. treasury securities
Debt Securities, Available-for-sale [Line Items]
Fair value	5,406	2,931
Gross unrealized losses	(3)	(1)
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Fair value	37,568	15,276
Gross unrealized losses	(45)	(21)
Municipal and agency notes and bonds
Debt Securities, Available-for-sale [Line Items]
Fair value	9,060	12,956
Gross unrealized losses	$ (10)	$ (16)

Lines of Credit - Narrative (De

Lines of Credit - Narrative (Details) - Committed Revolving Credit Line - USD ($)	Mar. 31, 2024	Dec. 22, 2021
Line of Credit \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Long-term debt	$ 0
JP Morgan Chase Bank, N.A. \| Letter of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity	30,000,000
JP Morgan Chase Bank, N.A. \| Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 50,000,000
JP Morgan Chase Bank, N.A. \| Line of Credit \| Letter of Credit
Line of Credit Facility [Line Items]
Utilized amount of the maximum allowable credit line	$ 20,300,000

Lines of Credit - Schedule of D

Lines of Credit - Schedule of Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Standby Letters of Credit
Line of Credit Facility [Line Items]
Outstanding letters of credit	$ 18,293	$ 19,945

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Benefit from income taxes	$ (1,285)	$ (1,159)
Discrete items	76	488
Benefit from income taxes, excluding discrete items	$ (1,209)	$ (671)
Effective tax rate	13.50%	15.50%
Effective tax rate, excluding discrete items	12.70%	9%

Segment Reporting - Schedule of

Segment Reporting - Schedule of Financial Information by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Revenue	$ 12,090	$ 13,401
Cost of revenue	4,955	5,246
Gross profit	7,135	8,155
Operating expenses:
General and administrative	7,566	7,066
Sales and marketing	6,152	4,894
Research and development	4,351	4,306
Total operating expenses	18,069	16,266
Loss from operations	(10,934)	(8,111)
Water
Segment Reporting Information [Line Items]
Revenue	12,089	13,296
Emerging Technologies
Segment Reporting Information [Line Items]
Revenue	1	105
Operating Segments
Segment Reporting Information [Line Items]
Revenue	12,090	13,401
Cost of revenue	4,955	5,246
Gross profit	7,135	8,155
Operating expenses:
General and administrative	2,940	2,906
Sales and marketing	5,552	4,345
Research and development	4,351	4,306
Total operating expenses	12,843	11,557
Loss from operations	(5,708)	(3,402)
Operating Segments \| Water
Segment Reporting Information [Line Items]
Revenue	12,089	13,296
Cost of revenue	4,954	5,101
Gross profit	7,135	8,195
Operating expenses:
General and administrative	1,922	1,938
Sales and marketing	3,745	3,175
Research and development	1,100	1,180
Total operating expenses	6,767	6,293
Loss from operations	368	1,902
Operating Segments \| Emerging Technologies
Segment Reporting Information [Line Items]
Revenue	1	105
Cost of revenue	1	145
Gross profit	0	(40)
Operating expenses:
General and administrative	1,018	968
Sales and marketing	1,807	1,170
Research and development	3,251	3,126
Total operating expenses	6,076	5,264
Loss from operations	(6,076)	(5,304)
Corporate
Operating expenses:
Total operating expenses	$ 5,226	$ 4,709

Concentrations - Schedules of C

Concentrations - Schedules of Concentration of Risk, by Risk Factor (Details) - Revenue from Contract with Customer Benchmark - Customer Concentration Risk - Water	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Customer A
Concentration Risk [Line Items]
Percentage of revenue		27%
Customer B
Concentration Risk [Line Items]
Percentage of revenue	18%
Customer C
Concentration Risk [Line Items]
Percentage of revenue	13%
Customer D
Concentration Risk [Line Items]
Percentage of revenue		11%