Inogen (INGN) 10-Q 5 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	Apr. 30, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Trading Symbol	INGN
Entity Registrant Name	INOGEN, INC.
Entity Central Index Key	0001294133
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		22,047,608
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, $0.001 par value
Security Exchange Name	NASDAQ
Entity File Number	001-36309
Entity Tax Identification Number	33-0989359
Entity Address, Address Line One	326 Bollay Drive
Entity Address, City or Town	Goleta
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	93117
City Area Code	(805)
Local Phone Number	562-0500
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	DE

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 208,362	$ 198,037
Marketable securities		11,057
Accounts receivable, net	40,396	34,325
Inventories, net	37,600	35,664
Income tax receivable	2,763	2,976
Prepaid expenses and other current assets	13,868	10,160
Total current assets	302,989	292,219
Property and equipment
Rental equipment, net	38,995	39,308
Manufacturing equipment and tooling	10,267	9,704
Computer equipment and software	7,533	7,266
Furniture and equipment	1,730	1,730
Leasehold improvements	4,398	4,388
Land and building	125	125
Construction in process	2,443	1,773
Total property and equipment	65,491	64,294
Less accumulated depreciation	(45,824)	(44,856)
Property and equipment, net	19,667	19,438
Goodwill	32,912	32,954
Intangible assets, net	75,282	77,533
Operating lease right-of-use asset	8,117	5,855
Deferred tax asset - noncurrent	14,652	14,452
Other assets	5,502	4,888
Total assets	459,121	447,339
Current liabilities
Accounts payable and accrued expenses	32,853	30,730
Accrued payroll	8,650	6,215
Warranty reserve - current	5,614	4,923
Operating lease liability - current	1,863	2,014
Deferred revenue - current	5,957	5,478
Income tax payable	908	821
Total current liabilities	55,845	50,181
Long-term liabilities
Warranty reserve - noncurrent	7,957	7,648
Operating lease liability - noncurrent	9,116	4,702
Earnout liability - noncurrent	25,607	26,559
Deferred revenue - noncurrent	13,211	13,541
Deferred tax liability - noncurrent	85	87
Total liabilities	111,821	102,718
Commitments and contingencies (Note 10)
Stockholders' equity
Common stock, $0.001 par value per share; 200,000,000 authorized; 22,044,527 and 22,031,410 shares issued and outstanding as of March 31, 2020 and December 31, 2019, respectively	22	22
Additional paid-in capital	267,011	263,252
Retained earnings	79,845	81,434
Accumulated other comprehensive income (loss)	422	(87)
Total stockholders' equity	347,300	344,621
Total liabilities and stockholders' equity	$ 459,121	$ 447,339

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	22,044,527	22,031,410
Common stock, shares outstanding	22,044,527	22,031,410

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue
Sales revenue	$ 83,140	$ 84,818
Rental revenue	5,349	5,384
Total revenue	88,489	90,202
Cost of revenue
Cost of sales revenue	47,118	42,067
Cost of rental revenue, including depreciation of $1,299 and $1,705, respectively	3,005	3,726
Total cost of revenue	50,123	45,793
Gross profit
Gross profit-sales revenue	36,022	42,751
Gross profit-rental revenue	2,344	1,658
Total gross profit	38,366	44,409
Operating expense
Research and development	3,605	1,669
Sales and marketing	27,163	28,201
General and administrative	9,777	9,681
Total operating expense	40,545	39,551
Income (loss) from operations	(2,179)	4,858
Other income (expense)
Interest income	552	1,334
Other income (expense)	(60)	(120)
Total other income, net	492	1,214
Income (loss) before provision (benefit) for income taxes	(1,687)	6,072
Provision (benefit) for income taxes	(98)	770
Net income (loss)	(1,589)	5,302
Other comprehensive income (loss), net of tax
Change in foreign currency translation adjustment	(158)	(137)
Change in net unrealized gains (losses) on foreign currency hedging	661	84
Less: reclassification adjustment for net (gains) losses included in net income	12	176
Total net change in unrealized gains (losses) on foreign currency hedging	673	260
Change in net unrealized gains (losses) on marketable securities	(6)	13
Total other comprehensive income, net of tax	509	136
Comprehensive income (loss)	$ (1,080)	$ 5,438
Basic net income (loss) per share attributable to common stockholders (Note 7)	$ (0.07)	$ 0.24
Diluted net income (loss) per share attributable to common stockholders (Note 7)	$ (0.07)	$ 0.24
Weighted-average number of shares used in calculating net income (loss) per share attributable to common stockholders:
Basic common shares	21,916,365	21,750,305
Diluted common shares	21,916,365	22,534,885

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Depreciation	$ 1,299	$ 1,705

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)
Beginning Balance at Dec. 31, 2018	$ 310,424	$ 22	$ 249,194	$ 60,484	$ 724
Beginning Balance, shares at Dec. 31, 2018		21,778,632
Stock-based compensation	3,586		3,586
Employee stock purchases	1,525		1,525
Employee stock purchases, shares		16,767
Restricted stock awards issued, net of forfeitures, shares		66,944
Vesting of restricted stock units	(59)		(59)
Vesting of restricted stock units, shares		11,265
Shares withheld related to net restricted stock settlement	(655)		(655)
Shares withheld related to net restricted stock settlement, shares		(12,045)
Stock options exercised	1,635		1,635
Stock options exercised, shares		69,779
Net income (loss)	5,302			5,302
Other comprehensive income	136				136
Ending Balance at Mar. 31, 2019	321,894	$ 22	255,226	65,786	860
Ending Balance, shares at Mar. 31, 2019		21,931,342
Beginning Balance at Dec. 31, 2019	344,621	$ 22	263,252	81,434	(87)
Beginning Balance, shares at Dec. 31, 2019		22,031,410
Stock-based compensation	2,784		2,784
Employee stock purchases	1,088		1,088
Employee stock purchases, shares		27,954
Restricted stock awards issued, net of forfeitures, shares		(27,729)
Vesting of restricted stock units	(7)		(7)
Vesting of restricted stock units, shares		10,167
Shares withheld related to net restricted stock settlement	(166)		(166)
Shares withheld related to net restricted stock settlement, shares		(3,609)
Stock options exercised	$ 60		60
Stock options exercised, shares	6,334	6,334
Net income (loss)	$ (1,589)			(1,589)
Other comprehensive income	509				509
Ending Balance at Mar. 31, 2020	$ 347,300	$ 22	$ 267,011	$ 79,845	$ 422
Ending Balance, shares at Mar. 31, 2020		22,044,527

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities
Net income (loss)	$ (1,589)	$ 5,302
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	4,462	2,794
Loss on rental units and other fixed assets	130	171
Gain on sale of former rental assets	(37)	(21)
Provision for sales revenue returns and doubtful accounts	3,608	4,428
Provision for rental revenue adjustments	808	590
Provision for inventory losses	347	456
Stock-based compensation expense	2,784	3,586
Deferred income taxes	(200)	834
Change in fair value of earnout liability	(952)
Changes in operating assets and liabilities:
Accounts receivable	(10,511)	(9,517)
Inventories	(3,721)	(2,897)
Income tax receivable	213	100
Prepaid expenses and other current assets	(3,710)	(2,143)
Operating lease right-of-use asset	(2,262)	(5,936)
Other noncurrent assets	460	(491)
Accounts payable and accrued expenses	2,759	(1,974)
Accrued payroll	2,436	(3,572)
Warranty reserve	1,000	227
Deferred revenue	149	367
Income tax payable	103	(277)
Operating lease liability	4,263	6,981
Other noncurrent liabilities		(832)
Net cash provided by (used in) operating activities	540	(1,824)
Cash flows from investing activities
Purchases of marketable securities		(19,033)
Maturities of marketable securities	11,051	13,750
Investment in property and equipment	(1,479)	(933)
Production and purchase of rental equipment	(735)	(781)
Proceeds from sale of former assets	62	49
Net cash provided by (used in) investing activities	8,899	(6,948)
Cash flows from financing activities
Proceeds from stock options exercised	60	1,635
Proceeds from employee stock purchases	1,088	1,525
Payment of employment taxes related to release of restricted stock	(173)	(714)
Net cash provided by financing activities	975	2,446
Effect of exchange rates on cash	(89)	(72)
Net increase (decrease) in cash and cash equivalents	10,325	(6,398)
Cash and cash equivalents, beginning of period	198,037	196,634
Cash and cash equivalents, end of period	208,362	190,236
Supplemental disclosures of cash flow information
Cash paid during the period for income taxes, net of refunds received		214
Supplemental disclosure of non-cash transactions
Property and equipment in accounts payable and accrued liabilities	$ 38	$ 194

Business Overview

Business Overview	3 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Business Overview	1. Business overview Inogen, Inc. (Company or Inogen) was incorporated in Delaware on November 27, 2001. The Company is a medical technology company that primarily develops, manufactures and markets innovative portable oxygen concentrators used to deliver supplemental long-term oxygen therapy to patients suffering from chronic respiratory conditions. Traditionally, these patients have relied on stationary oxygen concentrator systems for use in the home and oxygen tanks or cylinders for mobile use, which the Company calls the delivery model. The tanks and cylinders must be delivered regularly and have a finite amount of oxygen, which requires patients to plan activities outside of their homes around delivery schedules and a finite oxygen supply. Additionally, patients must attach long, cumbersome tubing to their stationary concentrators simply to enable mobility within their homes. The Company’s proprietary Inogen One ® Since adopting the Company’s direct-to-consumer rental strategy in 2009, the Company has directly sold or rented more than 829,000 of its Inogen oxygen concentrators as of March 31, 2020. The Company incorporated Inogen Europe Holding B.V., a Dutch limited liability company, on April 13, 2017. On May 4, 2017, Inogen Europe Holding B.V. acquired all issued and outstanding capital stock of MedSupport Systems B.V. (MedSupport) and began operating under the name Inogen Europe B.V. The Company merged Inogen Europe Holding B.V. and Inogen Europe B.V. on December 28, 2018. Inogen Europe B.V. is the remaining legal entity. Inogen completed the acquisition of New Aera, Inc. (New Aera) on August 9, 2019.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	2. Basis of presentation and summary of significant accounting policies The consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP). The results of operations for the three months ended March 31, 2020 shown in this report are not necessarily indicative of results to be expected for the full year ending December 31, 2020. In the opinion of the Company’s management, the information contained herein reflects all adjustments, consisting of only normal recurring adjustments, necessary for a fair presentation of the Company’s results of operations, financial position, cash flows and stockholders’ equity. Certain footnote disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to Securities and Exchange Commission (SEC) rules and regulations relating to interim financial statements. The accompanying consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K filed with the SEC on February 25, 2020. Except as further described below, there have been no significant changes in the Company’s accounting policies from those disclosed in its Annual Report on Form 10-K filed with the SEC on February 25, 2020. Basis of consolidation The consolidated financial statements include the accounts of Inogen, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated. Use of estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Management bases these estimates and assumptions upon historical experience, existing and known circumstances, authoritative accounting pronouncements and other factors that management believes to be reasonable. Significant areas requiring the use of management estimates relate to revenue recognition and determining the stand-alone selling price (SSP) of performance obligations, inventory and rental asset valuations and write-downs, accounts receivable allowances for bad debts, returns and adjustments, warranty expense, stock compensation expense, depreciation and amortization, income tax provision and uncertain tax positions, fair value of financial instruments, fair value of acquired intangible assets and goodwill and fair value of earnout liabilities. Actual results could differ from these estimates. Recently issued accounting pronouncements not yet adopted In December 2019, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The new guidance simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The new guidance also improves consistent application of and simplifies US GAAP for other areas of Topic 740 by clarifying and amending the existing guidance. currently evaluating the effect of the new guidance. Recently adopted accounting pronouncements In June 2016, the FASB issued ASU No. 2016-13, Accounting for Credit Losses (Topic 326) In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement Business segments The Company operates and reports in only one operating and reportable segment – development, manufacturing, marketing, sales, and rental of respiratory products. Management reports financial information on a consolidated basis to the Company’s chief operating decision maker.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2020
Business Combinations [Abstract]
Acquisitions	3. Acquisitions On August 6, 2019, the Company entered into an Agreement and Plan of Merger (Merger Agreement) by and among the Company, New Aera, Inc., a Delaware corporation, Move Merger Sub, Inc., a Delaware corporation and a wholly-owned subsidiary of the Company, and Gregory J. Kapust, as stockholder representative. On August 9, 2019, the Company completed the acquisition of New Aera pursuant to and on the terms set forth in the Merger Agreement. In connection with the Merger Agreement, the Company also separately acquired certain intellectual property assets from Silverbow Development, LLC, an affiliate of New Aera (Silverbow). New Aera is an innovative developer and manufacturer of portable non-invasive ventilators for people suffering from various chronic lung diseases. Goodwill associated with this acquisition is not expected to be deductible for income tax purposes. Assets and liabilities of the acquired company were recorded at their estimated fair values at the date of acquisition. The excess purchase price over the fair value of net tangible assets and identifiable intangible assets acquired has been allocated to goodwill. Goodwill represents the expected synergies with the existing business, the acquired assembled workforce, and future cash flows after the acquisition. The fair value assigned to the identifiable intangible asset was determined primarily by using the excess earnings method. T he key assumptions included in the excess earnings method included revenue recognized, cost of revenue and the discount rate. The fair value of the earnout liability was measured using a Monte Carlo simulation and was discounted using a rate that appropriately captures the risk associated with the obligation. The key assumption included in the simulation included revenue recognized Preliminary fair values of assets acquired and liabilities assumed have been updated for deferred taxes. The purchase accounting for this acquisition has been finalized. The following table summarizes the purchase price allocation for the acquisition of New Aera: Cash $ 122 Inventories 140 Other current assets 8 Property and equipment 224 Goodwill 30,742 Intangible assets 77,700 Total assets acquired $ 108,936 Deferred tax liability - noncurrent $ 12,664 Earnout liability - noncurrent 25,749 Total liabilities assumed 38,413 Total purchase price $ 70,523 The consolidated financial and operating results reflect the New Aera operations beginning August 9, 2019. The following unaudited pro forma information for the three months ended March 31, 2019 presents the revenue and net income assuming the acquisition of New Aera had occurred as of January 1, 2018. Three months ended March 31, 2019 Total revenue $ 90,207 Net income $ 2,650

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair value measurements Accounting Standards Codification (ASC) 820 — Fair Value Measurements and Disclosures Level input Input definition Level 1 Inputs are unadjusted, quoted prices for identical assets or liabilities in active markets at the measurement date. Level 2 Inputs, other than quoted prices included in Level 1, that are observable for the asset or liability through corroboration with market data at the measurement date. Level 3 Unobservable inputs that reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. The Company’s financial instruments consist of cash and cash equivalents, marketable securities, accounts receivable, accounts payable and accrued expenses. The carrying values of its financial instruments approximate fair value based on their short-term nature. Cash, cash equivalents and marketable securities The Company obtained the fair value of its available-for-sale investments, which are not in active markets, from a third-party professional pricing service using quoted market prices for identical or comparable instruments, rather than direct observations of quoted prices in active markets. The Company's professional pricing service gathers observable inputs for all of its fixed income securities from a variety of industry data providers (e.g., large custodial institutions) and other third-party sources. Once the observable inputs are gathered, all data points are considered, and the fair value is determined. The Company validates the quoted market prices provided by its primary pricing service by comparing their assessment of the fair values against the fair values provided by its investment managers. The Company's investment managers use similar techniques to its professional pricing service to derive pricing as described above. As all significant inputs were observable, derived from observable information in the marketplace or supported by observable levels at which transactions are executed in the marketplace, the Company has classified its marketable securities within Level 2 of the fair value hierarchy. The following table summarizes fair value measurements by level for the assets measured at fair value on a recurring basis for cash, cash equivalents and marketable securities: As of March 31, 2020 Gross Cash Adjusted unrealized and cash Marketable cost gains Fair value equivalents securities Cash $ 50,238 $ — $ 50,238 $ 50,238 $ — Level 1: Money market accounts 158,124 — 158,124 158,124 — Level 2: Corporate bonds — — — — — U.S. Treasury securities — — — — — Total $ 208,362 $ — $ 208,362 $ 208,362 $ — As of December 31, 2019 Gross Cash Adjusted unrealized and cash Marketable cost gains Fair value equivalents securities Cash $ 51,560 $ — $ 51,560 $ 51,560 $ — Level 1: Money market accounts 146,477 — 146,477 146,477 — Level 2: Corporate bonds 2,011 2 2,013 — 2,013 U.S. Treasury securities 9,038 6 9,044 — 9,044 Total $ 209,086 $ 8 $ 209,094 $ 198,037 $ 11,057 Derivative instruments and hedging activities The Company transacts business in foreign currencies and has international sales and expenses denominated in foreign currencies, subjecting the Company to foreign currency risk. The Company has entered into foreign currency forward contracts, generally with maturities of twelve months or less, to reduce the volatility of cash flows primarily related to forecasted revenue denominated in certain foreign currencies. These contracts allow the Company to sell Euros in exchange for U.S. dollars at specified contract rates. Forward contracts are used to hedge forecasted sales over specific months. Changes in the fair value of these forward contracts designed as cash flow hedges are recorded as a component of accumulated other comprehensive income (loss) within stockholders’ equity and are recognized in the consolidated statements of comprehensive income (loss) during the period which approximates the time the corresponding sales occur. The Company may also enter into foreign exchange contracts that are not designated as hedging instruments for financial accounting purposes. These contracts are generally entered into to offset the gains and losses on certain asset and liability balances until the expected time of repayment. Accordingly, any gains or losses resulting from changes in the fair value of the non-designated contracts are reported in other expense, net in the consolidated statements of comprehensive income. The gains and losses on these contracts generally offset the gains and losses associated with the underlying foreign currency-denominated balances, which are also reported in other income (expense), net. The Company records the assets or liabilities associated with derivative instruments and hedging activities at fair value based on Level 2 inputs in other current assets or other current liabilities, respectively, in the consolidated balance sheet. The Company had a related receivable of $436 and a related payable of $514 as of March 31, 2020 and December 31, 2019, respectively. The Company classifies the foreign currency derivative instruments within Level 2 in the fair value hierarchy as the valuation inputs are based on quoted prices and market observable data of whether it is designated and qualifies for hedge accounting. The Company documents the hedging relationship and its risk management objective and strategy for undertaking the hedge, the hedging instrument, the hedged transaction, the nature of the risk being hedged, how the hedging instrument’s effectiveness in offsetting the hedged risk will be assessed prospectively and retrospectively, and a description of the method used to measure ineffectiveness. The Company assesses hedge effectiveness and ineffectiveness at a minimum quarterly but may assess it monthly. For derivative instruments that are designed and qualify as part of a cash flow hedging relationship, the effective portion of the gain or loss on the derivative is reported in other comprehensive income (loss) and reclassified into earnings in the same periods during which the hedged transaction affects earnings. Gains and losses on the derivative representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness are recognized in current period earnings. The Company will discontinue hedge accounting prospectively when it determines that the derivative is no longer effective in offsetting cash flows attributable to the hedge risk. The cash flow hedge is de-designated because a forecasted transaction is not probable of occurring, or management determines to remove the designation of the cash flow hedge. In all situations in which hedge accounting is discontinued and the derivative remains outstanding, the Company continues to carry the derivative at its fair value on the balance sheet and recognizes any subsequent changes in the fair value in earnings. When it is probable that a forecasted transaction will not occur, the Company will discontinue hedge accounting and recognize immediately in earnings gains and losses that were accumulated in other comprehensive income (loss) related to the hedging relationship. Accumulated other comprehensive income (loss) The components of accumulated other comprehensive income (loss) were as follows: Foreign Unrealized Unrealized Accumulated currency gains on gains (losses) other translation marketable on cash comprehensive adjustments securities flow hedges income (loss) Balance as of December 31, 2019 $ 271 $ 6 $ (364 ) $ (87 ) Other comprehensive income (loss) (158 ) (6 ) 673 509 Balance as of March 31, 2020 $ 113 $ — $ 309 $ 422 Comprehensive income (loss) is the total net earnings and all other non-owner changes in equity. Except for net income (loss) and unrealized gains and losses on cash flow hedges, the Company does not have any transactions or other economic events that qualify as comprehensive income (loss). Earnout liability The Com pany has obligations to pay up to $31,400 in earnout payments in cash if certain future financial results are met. The earnout liability was valued using Level 3 inputs. The fair value of the earnout was determined by employing a Monte Carlo simulation in a risk-neutral framework. The underlying simulated variable includes recognized revenue. The recognized revenue volatility estimate was based on a study of historical asset volatility for a set of comparable public companies. The model includes other assumptions including the market price of risk, which was calculated as the weighted average cost of capital (WACC) less the long-term risk free rate. The earnout period for recognized revenue is each calendar year beginning with calendar year 2019 and ending on the calendar year in which the earnout consideration equals the earnout cap The following table provides quantitative information about Level 3 inputs for fair value measurement of the earnout liability as of March 31, 2020 and December 31, 2019. Significant increases or decreases in these inputs in isolation could result in a significant impact on our fair value measurement: As of As of Simulation input March 31, 2020 December 31, 2019 Revenue volatility 35.00 % 35.00 % WACC 12.50 % 13.00 % 20-year risk free rate 1.15 % 2.25 % Market price of risk 9.00 % 10.00 % The reconciliation of the earnout liability measured and carried at fair value on a recurring basis is as follows: Three months ended March 31, 2020 Balance at beginning of period $ 26,559 Change in fair value (952 ) Balance at end of period $ 25,607

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	5. Balance sheet components Cash, cash equivalents and marketable securities The Company considers all short-term highly liquid investments with a maturity of three months or less to be cash equivalents. The Company’s marketable debt securities are classified and accounted for as available-for-sale. Cash equivalents are recorded at cost plus accrued interest, which is considered adjusted cost, and approximates fair value. Marketable debt securities are included in cash equivalents and marketable securities based on the maturity date of the security. Short-term investments are included in marketable securities in the current period presentation. The Company considers investments with maturities greater than three months, but less than one year, to be marketable securities. Investments are reported at fair value with realized and unrealized gains or losses reported in other income (expense), net. The Company reviews its investments to identify and evaluate investments that have an indication of possible impairment. Factors considered in determining whether a loss is temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, and the Company's intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value. Credit losses and other-than-temporary impairments are declines in fair value that are not expected to recover and are charged to other income (expense), net. March 31, December 31, Cash and cash equivalents 2020 2019 Cash $ 50,238 $ 51,560 Money market accounts 158,124 146,477 Total cash and cash equivalents $ 208,362 $ 198,037 Marketable securities Corporate bonds $ — $ 2,013 U.S. Treasury securities — 9,044 Total marketable securities $ — $ 11,057 Accounts receivable and allowance for bad debts, returns, and adjustments Accounts receivable are customer obligations due under normal sales and rental terms. The Company performs credit evaluations of the customers’ financial condition and generally does not require collateral. The allowance for doubtful accounts is maintained at a level that, in management’s opinion, is adequate to absorb potential losses related to accounts receivable and is based upon the Company’s continuous evaluation of the collectability of outstanding balances. Management’s evaluation takes into consideration such factors as past bad debt experience, economic conditions and information about specific receivables. The Company’s evaluation also considers the age and composition of the outstanding amounts in determining their net realizable value. The allowance for doubtful accounts is based on estimates, and ultimate losses may vary from current estimates. As adjustments to these estimates become necessary, they are reported in general and administrative expense for sales revenue and as a reduction of rental revenue in the periods in which they become known. The allowance is increased by bad debt provisions, net of recoveries, and is reduced by direct write-offs. The Company generally does not allow returns from providers for reasons not covered under its standard warranty. Therefore, provision for returns applies primarily to direct-to-consumer sales. This reserve is calculated based on actual historical return rates under the Company’s 30-day return program and is applied to the related sales revenue for the last month of the quarter reported. The Company also records an allowance for rental revenue adjustments which is recorded as a reduction of rental revenue and net rental accounts receivable balances. These adjustments result from contractual adjustments, audit adjustments, untimely claims filings, or billings not paid due to another provider performing same or similar functions for the patient in the same period, all of which prevent billed revenue from becoming realizable. The reserve is based on historical revenue adjustments as a percentage of rental revenue billed and unbilled during the related period. When recording the allowance for doubtful accounts for sales revenue, the bad debt expense account (general and administrative expense account) is charged; when recording allowance for sales returns, the sales returns account (contra sales revenue account) is charged; and when recording the allowances for rental reserve adjustments and doubtful accounts, the rental revenue adjustments account (contra rental revenue account) is charged. As of March 31, 2020 and December 31, 2019, included in accounts receivable on the consolidated balance sheets were earned but unbilled receivables of $596 and $590, respectively. These balances reflect gross unbilled receivables prior to any allowances for adjustments and write-offs. The Company consistently applies its allowance estimation methodology from period-to-period. The Company’s best estimate is made on an accrual basis and adjusted in future periods as required. Any adjustments to the prior period estimates are included in the current period. As additional information becomes known, the Company adjusts its assumptions accordingly to change its estimate of the allowance. Gross accounts receivable balance concentrations by major category as of March 31, 2020 and December 31, 2019 were as follows: March 31, December 31, Gross accounts receivable 2020 2019 Rental (1) $ 3,442 $ 3,003 Business-to-business and other receivables (2) 38,706 33,101 Total gross accounts receivable $ 42,148 $ 36,104 Net accounts receivable (gross accounts receivable, net of allowances) balance concentrations by major category as of March 31, 2020 and December 31, 2019 were as follows: March 31, December 31, Net accounts receivable 2020 2019 Rental (1) $ 2,912 $ 2,464 Business-to-business and other receivables (2) 37,484 31,861 Total net accounts receivable $ 40,396 $ 34,325 (1) Rental includes Medicare, Medicaid/other government, private insurance and patient pay. (2) Business-to-business receivables included one customer with a gross accounts receivable balance of $8,978 and $10,695 as of March 31, 2020 and December 31, 2019, respectively. This customer received extended payment terms through a direct financing plan offered. The Company also has a credit insurance policy in place, which allocated up to $20,000 in coverage as of March 31, 2020 and allocated up to $20,000 in coverage as of December 31, 2019 for this customer with a $400 deductible and 10% retention. The following tables set forth the accounts receivable allowances as of March 31, 2020 and December 31, 2019: March 31, December 31, Allowances - accounts receivable 2020 2019 Doubtful accounts $ 167 $ 205 Rental revenue adjustments 409 411 Sales returns 1,176 1,163 Total allowances - accounts receivable $ 1,752 $ 1,779 Concentration of credit risk Financial instruments that potentially subject the Company to concentration of credit risk consist principally of cash, cash equivalents, marketable securities and accounts receivable. At times, cash account balances may be in excess of the amounts insured by the Federal Deposit Insurance Corporation (FDIC). However, management believes the risk of loss to be minimal. The Company performs periodic evaluations of the relative credit standing of these institutions and has not experienced any losses on its cash and cash equivalents to date. The Company has also entered into hedging relationships with a single counterparty to offset the forecasted Euro-based revenues. The credit risk has been reduced due to a net settlement arrangement whereby the Company is allowed to net settle transactions with a single net amount payable by one party to the other. Concentration of customers and vendors The Company primarily sells its products to traditional home medical equipment providers, distributors, and resellers in the United States and in foreign countries primarily on a credit basis. The Company also sells its products direct-to-consumers on a primarily prepayment basis. One single customer represented more than 10% of the Company’s total revenue for the three months ended March 31, 2020, and no single customer represented more than 10% of the Company’s total revenue for the three months ended March 31, 2019. Two customers each represented more than 10% of the Company’s net accounts receivable balance with accounts receivable balances of $10,341 and $8,978, respectively, as of March 31, 2020, and $10,695 and $5,228, respectively, as of December 31, 2019. The Company currently purchases raw materials from a limited number of vendors, which resulted in a concentration of three major vendors. The three major vendors supply the Company with raw materials used to manufacture the Company’s products. For the three months ended March 31, 2020, the Company’s three major vendors accounted for 23.6%, 15.2%, and 9.4%, respectively, of total raw material purchases. For the three months ended March 31, 2019, the Company’s three major vendors accounted for 20.6%, 11.6% and 11.4%, respectively, of total raw material purchases. A portion of revenue is earned from sales outside the United States. Approximately 68.7% and 72.5% of the non-U.S. revenue for the three months ended March 31, 2020 and March 31, 2019, respectively, were invoiced in Euros. A breakdown of the Company’s revenue from U.S. and non-U.S. sources for the three months ended March 31, 2020 and March 31, 2019, respectively, is as follows: Three months ended March 31, 2020 2019 U.S. revenue $ 68,406 $ 70,399 Non-U.S. revenue 20,083 19,803 Total revenue $ 88,489 $ 90,202 Inventories Inventories are stated at the lower of cost and net realizable value. Cost is determined using a standard cost method, including material, labor and manufacturing overhead, whereby the standard costs are updated at least quarterly to reflect approximate actual costs using the first-in, first-out (FIFO) method. The Company records adjustments at least quarterly to inventory for potentially excess, obsolete, slow-moving or impaired items. The Company recorded noncurrent inventory related to inventories that are expected to be realized or consumed after one year of $2,150 and $1,076 as of March 31, 2020 and December 31, 2019, respectively. Noncurrent inventories are primarily related to raw materials purchased in bulk to support long-term expected repairs to reduce costs and are classified in other assets. During the three months ended March 31, 2020 and March 31, 2019, $368 and $441, respectively, of inventory was transferred to rental equipment and was considered a noncash transaction in the production and purchase of rental equipment on the consolidated statements of cash flow. Inventories that are considered current consist of the following: March 31, December 31, 2020 2019 Raw materials and work-in-progress $ 33,066 $ 31,676 Finished goods 5,931 5,174 Less: reserves (1,397 ) (1,186 ) Inventories, net $ 37,600 $ 35,664 Property and equipment Property and equipment are stated at cost. Depreciation and amortization are calculated using the straight-line method over the assets’ estimated useful lives as follows: Rental equipment 1.5-5 years Manufacturing equipment and tooling 3-5 years Computer equipment and software 2-3 years Furniture and equipment 3-5 years Leasehold improvements Lesser of estimated useful life or remaining lease term Expenditures for additions, improvements and replacements are capitalized and depreciated to a salvage value of $0. Repair and maintenance costs on rental equipment are included in cost of rental revenue on the consolidated statements of comprehensive income. Repair and maintenance expense, which includes labor, parts and freight, for rental equipment was $524 and $662 for the three months ended March 31, 2020 and March 31, 2019, respectively. Included within property and equipment is construction in process, primarily related to the design and engineering of tooling, jigs and other machinery. In addition, this item also includes computer software or development costs that have been purchased but have not completed the final configuration process for implementation into the Company’s systems. These items have not been placed in service; therefore, no depreciation or amortization was recognized for these items in the respective periods. Depreciation and amortization expense related to rental equipment and other property and equipment are summarized below for the three months ended March 31, 2020 and March 31, 2019, respectively. Three months ended March 31, 2020 2019 Rental equipment $ 1,299 $ 1,705 Other property and equipment 921 761 Total depreciation and amortization $ 2,220 $ 2,466 Property and equipment and rental equipment with associated accumulated depreciation is summarized below as of March 31, 2020 and December 31, 2019, respectively. March 31, December 31, Property and equipment 2020 2019 Rental equipment, net of allowances of $395 and $395, respectively $ 38,995 $ 39,308 Other property and equipment 26,496 24,986 Property and equipment 65,491 64,294 Accumulated depreciation Rental equipment 31,035 30,984 Other property and equipment 14,789 13,872 Accumulated depreciation 45,824 44,856 Property and equipment, net Rental equipment, net of allowances of $395 and $395, respectively 7,960 8,324 Other property and equipment 11,707 11,114 Property and equipment, net $ 19,667 $ 19,438 Long-lived assets The Company accounts for the impairment and disposition of long-lived assets in accordance with ASC 360 — Property, Plant, and Equipment Goodwill The changes in the carrying amount of goodwill for the three months ended March 31, 2020 were as follows: Balance as of December 31, 2019 $ 32,954 Translation adjustment (42 ) Balance as of March 31, 2020 $ 32,912 Intangible assets There were no impairments recorded related to the Company’s intangible assets as of March 31, 2020 and March 31, 2019. Amortization expense for intangible assets for the three months ended March 31, 2020 and March 31, 2019 was $2,242 and $328, respectively. The following tables represent the changes in net carrying values of intangible assets as of the respective dates: Average estimated Gross useful lives carrying Accumulated March 31, 2020 (in years) amount amortization Net amount Technology 10 $ 77,700 $ 4,856 $ 72,844 Licenses 10 185 167 18 Patents and websites 5 4,274 2,479 1,795 Customer relationships 4 1,320 963 357 Commercials 2-3 777 509 268 Total $ 84,256 $ 8,974 $ 75,282 Average estimated Gross useful lives carrying Accumulated December 31, 2019 (in years) amount amortization Net amount Technology 10 $ 77,700 $ 2,914 $ 74,786 Licenses 10 185 165 20 Patents and websites 5 4,274 2,308 1,966 Customer relationships 4 1,346 897 449 Commercials 2-3 777 465 312 Total $ 84,282 $ 6,749 $ 77,533 Annual estimated amortization expense for each of the succeeding fiscal years is as follows: March 31, 2020 Remaining 9 months of 2020 $ 6,722 2021 8,678 2022 8,367 2023 7,792 2024 7,787 Thereafter 35,936 $ 75,282 Current liabilities Accounts payable and accrued expenses as of March 31, 2020 and December 31, 2019 consisted of the following: March 31, December 31, 2020 2019 Accounts payable $ 18,727 $ 16,399 Accrued inventory (in-transit and unvouchered receipts) and trade payables 11,129 11,124 Accrued purchasing card liability 1,940 1,675 Accrued franchise, sales and use taxes 501 713 Other accrued expenses 556 819 Accounts payable and accrued expenses $ 32,853 $ 30,730 Accrued payroll as of March 31, 2020 and December 31, 2019 consisted of the following: March 31, December 31, 2020 2019 Accrued bonuses $ 1,143 $ 87 Accrued wages and other payroll related items 4,939 3,158 Accrued vacation 2,262 2,169 Accrued employee stock purchase plan deductions 306 801 Accrued payroll $ 8,650 $ 6,215

Leases

Leases	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Leases	6. Leases The Company has entered into operating leases primarily for commercial buildings. These leases have terms which range from 2 years to 8 years, some of which include options to extend the leases for up to 5 years. There are no economic penalties for the Company to extend the lease, and it is not reasonably assured that the Company will exercise the extension options. Operating lease right-of-use assets and liabilities commencing after January 1, 2019 are recognized at commencement date based on the present value of lease payments over the lease term. The operating leases do not contain material residual value guarantees or material restrictive covenants. T he Company leases a property owned by a related party. Operating lease cost for the property was $8 for the three months ended March 31, 2020, which was included in the total operating lease cost. Information related to the Company's right-of-use assets and related operating lease liabilities were as follows: Three months ended March 31, 2020 2019 Cash paid for operating lease liabilities $ 593 $ 576 Operating lease cost 632 544 Non-cash right-of-use assets obtained in exchange for new operating lease obligations 2,809 6,418 Weighted-average remaining lease term 2.5 years 3.1 years Weighted-average discount rate 3.7 % 3.8 % Maturities of lease liabilities due in the 12-month period ending March 31, 2021 $ 2,205 2022 2,057 2023 1,737 2024 1,725 2025 1,133 Thereafter 3,521 12,378 Less imputed interest (1,399 ) Total lease liabilities $ 10,979 Operating lease liability - current $ 1,863 Operating lease liability - noncurrent $ 9,116 Total lease liabilities $ 10,979 As of March 31, 2020, the Company has additional operating leases for its corporate headquarters in California and industrial space in Texas that have not yet commenced, with total minimum lease payments of $21,548. Lease payments for its corporate headquarters will increase annually by the lesser of the change, if any, in the Consumer Price Index of the Bureau of Labor Statistics of the U.S. Department of Labor or three and one-half percent (3.5%) at each annual adjustment date thereafter. Lease payments for the Company’s industrial space in Texas will increase annually by two and one-half percent (2.5%) at each annual adjustment date thereafter. These operating leases are estimated to commence in the third and fourth quarters of 2020 with a lease term of 10-11 years. This table excludes lease payments that were not fixed at commencement or modification.

Earnings (Loss) per Share

Earnings (Loss) per Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Earnings (Loss) per Share	7. Earnings (loss) per share Earnings (loss) per share (EPS) is computed in accordance with ASC 260 —Earnings per Share Basic earnings (loss) per share is calculated using the Company’s weighted-average outstanding common shares. Diluted earnings (loss) per share is calculated using the Company’s weighted-average outstanding common shares including the dilutive effect of stock awards as determined under the treasury stock method. The computation of EPS is as follows: Three months ended March 31, 2020 2019 Numerator—basic and diluted: Net income (loss) $ (1,589 ) $ 5,302 Denominator: Weighted-average common shares - basic common stock (1) 21,916,365 21,750,305 Weighted-average common shares - diluted common stock 21,916,365 22,534,885 Net income (loss) per share - basic common stock $ (0.07 ) $ 0.24 Net income (loss) per share - diluted common stock (2) $ (0.07 ) $ 0.24 Denominator calculation from basic to diluted: Weighted-average common shares - basic common stock (1) 21,916,365 21,750,305 Stock options and other dilutive awards 327,891 784,580 Weighted-average common shares - diluted common stock 22,244,256 22,534,885 Shares excluded from diluted weighted-average shares: Stock options 81,220 — Restricted stock units and restricted stock awards 293,236 119,378 Shares excluded from diluted weighted-average shares 374,456 119,378 (1) Unvested restricted stock units and restricted stock awards are not included as shares outstanding in the calculation of basic earnings (loss) per share. Vested restricted stock units and restricted stock awards are included in basic earnings (loss) per share if all vesting and performance criteria have been met. Performance-based restricted stock units and restricted stock awards are included in the number of shares used to calculate diluted earnings (loss) per share as long as all applicable performance criteria are met, and their effect is dilutive. Restricted stock awards are eligible to receive all dividends declared on the Company’s common shares during the vesting period; however, such dividends are not paid until the restrictions lapse. (2) Due to a net loss for the three months ended March 31, 2020, dilutive loss per share is the same as basic. The computations of diluted net income (loss) attributable to common stockholders exclude common stock options, restricted stock units, and restricted stock awards, which were anti-dilutive for the three months ended March 31, 2019.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	8. Income taxes The Company accounts for income taxes in accordance with ASC 740 —Income Taxes The Company accounts for uncertainties in income tax in accordance with ASC 740-10 —Accounting for Uncertainty in Income Taxes The Company recognizes interest and penalties on taxes, if any, within its income tax provision on its consolidated statements of comprehensive income. No significant interest or penalties were recognized during the periods presented. The Company operates in several taxing jurisdictions, including U.S. federal, multiple U.S. states and the Netherlands. The statute of limitations has expired for all tax years prior to 2016 for federal and prior to 2015 to 2016 for various state tax purposes. However, the net operating loss generated on the Company’s federal and state tax returns in prior years may be subject to adjustments by the federal and state tax authorities. The Company determined the income tax provision for interim periods using an estimate of the Company’s annual effective tax rate, adjusted for discrete items arising in that quarter. In each quarter, the Company updates its estimated annual effective tax rate, and if the estimated annual effective

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ equity The Company has a 2002 Stock Incentive Plan (2002 Plan) as amended, under which the Company granted options to purchase shares of its common stock. As of March 31, 2020, options to purchase 333 shares of common stock remained outstanding under the 2002 Plan. The 2002 Plan was terminated in March 2012 in connection with the adoption of the 2012 Plan, and, accordingly, no new options are available for issuance under this plan. The 2002 Plan continues to govern outstanding awards granted thereunder. The Company has a 2012 Equity Incentive Plan (2012 Plan) under which the Company granted options to purchase shares of its common stock. As of March 31, 2020, options to purchase 138,736 shares of common stock remained outstanding under the 2012 Plan. The 2012 Plan was terminated in connection with the Company’s initial public offering in February 2014, and accordingly, no new options are available for issuance under this plan. The 2012 Plan continues to govern outstanding awards granted thereunder. The Company has a 2014 Equity Incentive Plan (2014 Plan) that provides for the grant of incentive stock options, within the meaning of Section 422 of the Internal Revenue Code, to the Company’s employees and any parent and subsidiary corporation’s employees, and for the grant of nonstatutory stock options, restricted stock, restricted stock units, restricted stock awards, stock appreciation rights, performance units and performance shares to its employees, directors and consultants and its parent and subsidiary corporations’ employees and consultants. As of March 31, 2020, awards with respect to 1,217,373 shares of the Company’s common stock were outstanding, and 1,643,970 shares of common stock remained available for issuance under the 2014 Plan. The shares available for issuance under the 2014 Plan will be increased by any shares returned to the 2002 Plan, 2012 Plan and the 2014 Plan as a result of expiration or termination of awards (provided that the maximum number of shares that may be added to the 2014 Plan pursuant to such previously granted awards under the 2002 Plan and 2012 Plan is 2,328,569 shares). The number of shares available for issuance under the 2014 Plan also is increased annually on the first day of each fiscal year by an amount equal to the least of: • 895,346 • 4 • such other amount as the Company’s board of directors may determine. For 2020, no additional shares were added to the 2014 Plan share reserve pursuant to the provision described above. Stock options Options typically expire between seven and ten years from the date of grant and vest over one to four year terms. Options have been granted to employees, directors and consultants of the Company, as determined by the board of directors, at the deemed fair market value of the shares underlying the options at the date of grant. The activity for stock options under the Company’s stock plans for the three months ended March 31, 2020 is as follows: Remaining weighted- Weighted- average Per share average contractual average Price per exercise terms intrinsic Options share price (in years) value Outstanding as of December 31, 2019 980,884 $0.75-$83.30 $ 35.24 2.84 $ 34.07 Granted — — — Exercised (6,334 ) 1.17-24.52 9.42 Forfeited (1,876 ) 44.19-56.72 52.54 Expired — — — Outstanding as of March 31, 2020 972,674 0.75-83.30 35.38 2.59 18.39 Vested and exercisable as of March 31, 2020 953,431 0.75-83.30 35.20 2.58 18.61 Vested and expected to vest as of March 31, 2020 971,431 $0.75-$83.30 $ 35.37 2.59 $ 18.40 The total intrinsic value of options exercised during the three months ended March 31, 2020 and March 31, 2019 was $239 and $6,733, respectively. The unrecognized compensation expense related to non-vested stock-based compensation granted under the Plans as of March 31, 2020 was $163. This amount is expected to be recognized over a weighted-average period of 0.1 years. Stock incentive awards The Company grants restricted stock units (RSUs) and restricted stock awards (RSAs) under the 2014 Plan (Stock Awards). The Stock Awards vest either based solely on the satisfaction of time-based service conditions or on the satisfaction of time-based service conditions combined with performance criteria. Stock Awards are subject to forfeiture if the holder’s services to the Company terminate before vesting. Stock Awards granted with only time-based service vesting conditions generally vest over a four-year three-year Stock Awards activity for the three months ended March 31, 2020 is summarized below: Weighted- average grant Performance date fair and value Restricted stock units Time-based time-based Total per share Unvested restricted stock units as of December 31, 2019 108,976 3,134 112,110 $ 83.48 Granted 145,413 58,972 204,385 45.78 Vested (10,309 ) — (10,309 ) 107.85 Forfeited/canceled (4,293 ) (3,134 ) (7,427 ) 100.06 Unvested restricted stock units as of March 31, 2020 (1) 239,787 58,972 298,759 $ 56.44 Unvested and expected to vest restricted stock units outstanding as of March 31, 2020 263,337 $ 57.23 Weighted- average grant Performance date fair and value Restricted stock awards Time-based time-based Total per share Unvested restricted stock awards outstanding as of December 31, 2019 71,070 62,628 133,698 $ 95.74 Granted — — — — Vested (8,301 ) — (8,301 ) 108.51 Forfeited/canceled — (29,273 ) (29,273 ) 110.27 Unvested restricted stock awards outstanding as of March 31, 2020 (1) 62,769 33,355 96,124 $ 90.97 Unvested and expected to vest restricted stock awards outstanding as of March 31, 2020 76,815 $ 90.08 (1) Outstanding restricted stock units and restricted stock awards are based on the maximum payout of the targeted number of shares. As of March 31, 2020, the unrecognized compensation cost related to unvested employee restricted stock units and restricted stock awards was $18,992, excluding estimated forfeitures. This amount is expected to be recognized over a weighted-average period of 2.9 years. Employee stock purchase plan The Company’s 2014 Employee Stock Purchase Plan (ESPP) provides for the grant to all eligible employees an option to purchase stock under the ESPP, within the meaning Section 423 of the Internal Revenue Code. The ESPP permits participants to purchase common stock through payroll deductions of up to 15% of their eligible compensation, which includes a participant’s base straight time gross earnings, incentive compensation, bonuses, overtime and shift premium, but exclusive of payments for equity compensation and other similar compensation. A participant may purchase a maximum of 1,500 shares during a purchase period. Amounts deducted and accumulated by the participant are used to purchase shares of the Company’s common stock at the end of each six-month period. The purchase price of the shares will be 85% of the lower of the fair market value of the Company’s common stock on the first trading day of each offering period or on the exercise date. The offering periods are currently approximately six months in length beginning on the first business day on or after March 1 and September 1 of each year and ending on the first business day on or after September 1 and March 1 approximately six months later. As of March 31, 2020, a total of 670,678 shares of common stock were available for sale pursuant to the ESPP. The number of shares available for sale under the ESPP is increased annually on the first day of each fiscal year by an amount equal to the least of: • 179,069 • 1.5 • such other amount as may be determined by the administrator. For 2020, no additional shares were added to the ESPP share reserve pursuant to the provision described above. Stock-based compensation Stock-based compensation expense recognized for the three months ended March 31, 2020 and March 31, 2019, was as follows: Three months ended March 31, 2020 2019 Stock-based compensation expense by type of award: Stock option plan awards $ 525 $ 1,147 Restricted stock units and restricted stock awards 2,083 2,257 Employee stock purchase plan 176 182 Total stock-based compensation expense $ 2,784 $ 3,586 Employee stock-based compensation expense was calculated based on awards of stock options, restricted stock units and restricted stock awards ultimately expected to vest based on the Company’s historical award cancellations. The employee stock-based compensation expense recognized for the three months ended March 31, 2020 and March 31, 2019 has been reduced for estimated forfeitures of stock option plan awards at a rate of 7.3% and 7.3%, respectively. ASC 718 – Compensation-Stock Compensation For the three months ended March 31, 2020 and March 31, 2019, respectively, stock-based compensation expense recognized under ASC 718, included in cost of revenue, research and development expense, sales and marketing expense, and general and administrative expense was as follows: Three months ended March 31, 2020 2019 Cost of revenue $ 229 $ 285 Research and development 320 377 Sales and marketing 612 690 General and administrative 1,623 2,234 Total stock-based compensation expense $ 2,784 $ 3,586 401(k) retirement savings plan The Company maintains a 401(k) retirement savings plan for the benefit of eligible employees. Under the terms of this plan, eligible employees are able to make contributions to the plan on a tax-deferred basis. The Company began matching employees’ contributions, effective January 1, 2017. The Company contributed $252 and $318, net of forfeitures, to the 401(k) plan for the three months ended March 31, 2020 and March 31, 2019, respectively.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and contingencies Non-cancelable contractual obligations The Company enters into non-cancelable contractual obligations for software licenses and maintenance agreements. As of March 31, 2020, the minimum aggregate payments due under specified non-cancelable contractual obligations are summarized as follows: Non-cancelable contractual obligations Remaining 9 months of 2020 $ 433 2021 457 2022 — 2023 — 2024 — Thereafter — $ 890 Purchase obligations The Company had approximately $61,400 of outstanding purchase orders with its outside vendors and suppliers as of March 31, 2020. Warranty obligations The following table identifies the changes in the Company’s aggregate product warranty liabilities for the three and twelve-month periods ended March 31, 2020 and December 31, 2019, respectively: March 31, December 31, 2020 2019 Product warranty liability at beginning of period $ 12,571 $ 9,530 Accruals for warranties issued 2,650 8,131 Adjustments related to preexisting warranties (including changes in estimates) — 1,433 Settlements made (in cash or in kind) (1,650 ) (6,523 ) Product warranty liability at end of period $ 13,571 $ 12,571 Contract Liabilities Contract liabilities primarily consist of deferred revenue related to lifetime warranties on direct-to-consumer sales revenue when payments are received in advance of services performed under the contract. The contract with the customer states the final terms of the sale, including the description, quantity, and price of each product or service purchase. The increase in deferred revenue related to lifetime warranties for the three months ended March 31, 2020 was primarily driven by $1,648 of payments received in advance of satisfying performance obligations, partially offset by $1,289 of revenue recognized that were included in the deferred revenue balances as of December 31, 2019. Deferred revenue related to lifetime warranties was $18,087 and $17,728 as of March 31, 2020 and December 31, 2019, respectively, and is classified within deferred revenue – current and deferred revenue – noncurrent in the consolidated balance sheet. Legislation and HIPAA The healthcare industry is subject to numerous laws and regulations of federal, state and local governments. These laws and regulations include, but are not necessarily limited to, matters such as licensure, accreditation, government healthcare program participation requirements, reimbursement for patient services, and Medicare and Medicaid fraud and abuse. Government activity has continued with respect to investigations and allegations concerning possible violations of fraud and abuse statutes and regulations by healthcare providers. Violations of these laws and regulations could result in exclusion from government healthcare programs together with the imposition of significant fines and penalties, as well as significant repayments for patient services previously billed. The Company believes that it is in compliance in all material respects with applicable fraud and abuse regulations and other applicable government laws and regulations. Compliance with such laws and regulations can be subject to future government review and interpretation as well as regulatory actions unknown or unasserted at this time. The Health Insurance Portability and Accountability Act of 1996 (HIPAA) was enacted to en sure health insurance portability, reduce healthcare fraud and abuse, guarantee security and privacy of health information, and enforce standards for health information. The Health Information Technology for Economic and Clinical Health Act (HITECH Act) , in part, imposes notification requirements of certain security breaches relating to protected health information. The Company believes that it complies in all material respects with the provisions of those regulations that are applicable to the Company’s business. Legal proceedings Intellectual property lawsuit On November 21, 2019, Breathe Technologies, Inc. (Breathe), a subsidiary of Hill-Rom Holdings, filed a lawsuit against Inogen, Inc., New Aera, Inc., Silverbow Development, LLC, and Todd W. Allum in the United States District Court for the Northern District of California (N.D. Cal. Lawsuit). Breathe alleged: willful infringement of the ‘250 patent assigned to Breathe; that inventorship was incorrectly assigned and that Breathe owns rights to certain patents filed by New Aera, Inc. and Silverbow Development LLC; breach of contract; inducing breach of contract; interference with contract; and violation of California Business and Professional Code Section 17200. The complaint seeks to correct inventorship of certain patents now owned by the Company, injunctive relief, compensatory and punitory damages in an unspecified amount including trebling of all damages awarded with respect to infringement of the ‘250 patent, costs and expenses, including attorneys’ fees and expert fees, prejudgment and post-judgment interest and such other relief as the court deems proper. On March 31, 2020, Breathe filed a First Amended Complaint in which it dropped the patent infringement claims in the N.D. Cal. Lawsuit and added another claim for violation of California Business and Professional Code Section 17200. On the same day, Breathe re-filed the ‘250 patent infringement claims in the United States District Court for the Central District of California (C.D. Cal. Lawsuit). Both of these lawsuits are stayed until June 2020. The Company intends to vigorously defend itself against the allegations in both lawsuits should the stays be lifted. Securities class action and derivative lawsuits On March 6, 2019, plaintiff William Fabbri filed a lawsuit against Inogen, Scott Wilkinson, and Alison Bauerlein, in the United States District Court for the Central District of California on behalf of a purported class of purchasers of the Company’s securities. On March 21, 2019, plaintiff Steven Friedland filed a substantially similar lawsuit against the same defendants in the same court. On May 20, 2019, the court issued an order consolidating the two lawsuits under the name In re Inogen, Inc. Sec. Litig., O On June 26, 2019, plaintiff Twana Brown filed a shareholder derivative lawsuit against Inogen, Scott Wilkinson, Alison Bauerlein, Benjamin Anderson-Ray, Scott Beardsley, R. Scott Greer, Raymond Huggenberger, Heath Lukatch, Loren McFarland, and Heather Rider in the United States District Court for the Central District of California. The complaint purports to bring claims on behalf of Inogen against the individual defendants for breaches of their fiduciary duties as directors and/or officers of Inogen, unjust enrichment, waste of corporate assets and violations of section 14(a) of the Securities Exchange Act of 1934, as amended. The complaint generally alleges similar claims to the securities class action. The complaint seeks compensatory damages and restitution in an unspecified amount, changes to the Company’s corporate governance and internal procedures, costs and expenses, including attorneys’ fees and expert fees, and such other relief as the court deems proper. On August 5, 2019, the court issued an order staying the derivative action pending the resolution of the motion to dismiss stage in In re Inogen, Inc. Sec. Litig Between October 7, 2019 and October 31, 2019, three additional shareholder derivative complaints On January 13, 2020, the court consolidated the four derivative lawsuits before it under the name In re Inogen, Inc. S’holder Deriv. Litig. , Lead Case No. 2:19-cv-5568-FMO-AGR and ordered that the consolidated action be stayed pending the resolution of the motion to dismiss stage in In re Inogen, Inc., Sec. Litig. On September 13, 2019, plaintiff Dustin Weller filed a shareholder derivative lawsuit against Inogen, Scott Wilkinson, Alison Bauerlein, Benjamin Anderson-Ray, Scott Beardsley, R. Scott Greer, Raymond Huggenberger, Heath Lukatch, Loren McFarland, and Heather Rider in the United States District Court for the District of Delaware captioned Weller v. Wilkinson, et al. , No. 1:19-cv-01723-MN. On October 17, 2019, plaintiff Sharokh Soltanipour filed a shareholder derivative lawsuit against the same defendants in the same court, captioned Soltanipour v. Wilkinson, et al. , No. 1:19-cv-1968-MN. The complaints generally allege similar claims to those in In re Inogen, Inc., S’holder Deriv. Litig. The complaints purport to bring claims on behalf of Inogen compensatory damages in unspecified amounts, changes to the Company’s corporate governance and internal procedures, return of compensation, disgorgement of profits from sale of stock, costs and expenses, including attorneys’ fees and expert fees, and such other relief as the court deems proper. On December 23, 2019 and January 6, 2020, plaintiffs filed cross-motions to consolidate the two cases and to appoint lead counsel. Other litigation In addition to the lawsuits discussed above, the Company is party to various legal proceedings arising in the normal course of business. The Company carries insurance, subject to specified deductibles under the policies, to protect against losses from certain types of legal claims. At this time, the Company does not anticipate that any of these other proceedings arising in the normal course of business will have a material adverse effect on the Company’s business. Regardless of the outcome, litigation can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources, and other factors.

Foreign Currency Exchange Contr

Foreign Currency Exchange Contracts and Hedging	3 Months Ended
	Mar. 31, 2020
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Foreign currency exchange contracts and hedging	11. Foreign currency exchange contracts and hedging As of March 31, 2020 and March 31, 2019, the Company’s total non-designated and designated derivative contracts had notional amounts totaling approximately $3,885 and $23,788, respectively, and $2,369 and $16,072, respectively. These contracts were comprised of offsetting contracts with the same counterparty, each expires within one to nine months. During the three months ended March 31, 2020 and March 31, 2019, these contracts had, net of tax, an unrealized gain of $673 and $260, respectively. The nonperformance risk of the Company and the counterparty did not have a material impact on the fair value of the derivatives. During the three months ended March 31, 2020 and March 31, 2019, there were no ineffective portions relating to these hedges and the hedges remained effective through their respective settlement dates. As of March 31, 2020, the Company had eight designated hedges and one non-designated hedge. As of March 31, 2019, the Company had twenty-two designated hedges and three non-designated hedges.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Basis of Consolidation	Basis of consolidation The consolidated financial statements include the accounts of Inogen, Inc. and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated.
Use of Estimates	Use of estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Management bases these estimates and assumptions upon historical experience, existing and known circumstances, authoritative accounting pronouncements and other factors that management believes to be reasonable. Significant areas requiring the use of management estimates relate to revenue recognition and determining the stand-alone selling price (SSP) of performance obligations, inventory and rental asset valuations and write-downs, accounts receivable allowances for bad debts, returns and adjustments, warranty expense, stock compensation expense, depreciation and amortization, income tax provision and uncertain tax positions, fair value of financial instruments, fair value of acquired intangible assets and goodwill and fair value of earnout liabilities. Actual results could differ from these estimates.
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently issued accounting pronouncements not yet adopted In December 2019, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The new guidance simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740. The new guidance also improves consistent application of and simplifies US GAAP for other areas of Topic 740 by clarifying and amending the existing guidance. currently evaluating the effect of the new guidance.
Recently Adopted Accounting Pronouncements	Recently adopted accounting pronouncements In June 2016, the FASB issued ASU No. 2016-13, Accounting for Credit Losses (Topic 326) In January 2017, the FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement
Business Segments	Business segments The Company operates and reports in only one operating and reportable segment – development, manufacturing, marketing, sales, and rental of respiratory products. Management reports financial information on a consolidated basis to the Company’s chief operating decision maker.

Acquisitions (Tables)

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2020
Business Combinations [Abstract]
Summary of Purchase Price Allocation for Acquisition	The following table summarizes the purchase price allocation for the acquisition of New Aera: Cash $ 122 Inventories 140 Other current assets 8 Property and equipment 224 Goodwill 30,742 Intangible assets 77,700 Total assets acquired $ 108,936 Deferred tax liability - noncurrent $ 12,664 Earnout liability - noncurrent 25,749 Total liabilities assumed 38,413 Total purchase price $ 70,523
Summary of Unaudited Pro Forma Information	The consolidated financial and operating results reflect the New Aera operations beginning August 9, 2019. The following unaudited pro forma information for the three months ended March 31, 2019 presents the revenue and net income assuming the acquisition of New Aera had occurred as of January 1, 2018. Three months ended March 31, 2019 Total revenue $ 90,207 Net income $ 2,650

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Summary of Fair Value Assets Measured on Recurring Basis for Cash, Cash Equivalents and Marketable Securities	The following table summarizes fair value measurements by level for the assets measured at fair value on a recurring basis for cash, cash equivalents and marketable securities: As of March 31, 2020 Gross Cash Adjusted unrealized and cash Marketable cost gains Fair value equivalents securities Cash $ 50,238 $ — $ 50,238 $ 50,238 $ — Level 1: Money market accounts 158,124 — 158,124 158,124 — Level 2: Corporate bonds — — — — — U.S. Treasury securities — — — — — Total $ 208,362 $ — $ 208,362 $ 208,362 $ — As of December 31, 2019 Gross Cash Adjusted unrealized and cash Marketable cost gains Fair value equivalents securities Cash $ 51,560 $ — $ 51,560 $ 51,560 $ — Level 1: Money market accounts 146,477 — 146,477 146,477 — Level 2: Corporate bonds 2,011 2 2,013 — 2,013 U.S. Treasury securities 9,038 6 9,044 — 9,044 Total $ 209,086 $ 8 $ 209,094 $ 198,037 $ 11,057
Summary of Components of Accumulated Other Comprehensive Income (Loss)	The components of accumulated other comprehensive income (loss) were as follows: Foreign Unrealized Unrealized Accumulated currency gains on gains (losses) other translation marketable on cash comprehensive adjustments securities flow hedges income (loss) Balance as of December 31, 2019 $ 271 $ 6 $ (364 ) $ (87 ) Other comprehensive income (loss) (158 ) (6 ) 673 509 Balance as of March 31, 2020 $ 113 $ — $ 309 $ 422
Summary of Quantitative Information about Level 3 Inputs for Fair Value Measurement of Earnout Liability	The following table provides quantitative information about Level 3 inputs for fair value measurement of the earnout liability as of March 31, 2020 and December 31, 2019. Significant increases or decreases in these inputs in isolation could result in a significant impact on our fair value measurement: As of As of Simulation input March 31, 2020 December 31, 2019 Revenue volatility 35.00 % 35.00 % WACC 12.50 % 13.00 % 20-year risk free rate 1.15 % 2.25 % Market price of risk 9.00 % 10.00 %
Summary of Reconciliation of Earnout Liability Measured and Carried Fair Value on a Recurring Basis	The reconciliation of the earnout liability measured and carried at fair value on a recurring basis is as follows: Three months ended March 31, 2020 Balance at beginning of period $ 26,559 Change in fair value (952 ) Balance at end of period $ 25,607

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Summary of Cash, Cash Equivalents and Short-term Investments	Cash, cash equivalents, and marketable securities consist of the following: March 31, December 31, Cash and cash equivalents 2020 2019 Cash $ 50,238 $ 51,560 Money market accounts 158,124 146,477 Total cash and cash equivalents $ 208,362 $ 198,037 Marketable securities Corporate bonds $ — $ 2,013 U.S. Treasury securities — 9,044 Total marketable securities $ — $ 11,057
Schedule of Gross Accounts Receivable Balance Concentrations by Major Category	Gross accounts receivable balance concentrations by major category as of March 31, 2020 and December 31, 2019 were as follows: March 31, December 31, Gross accounts receivable 2020 2019 Rental (1) $ 3,442 $ 3,003 Business-to-business and other receivables (2) 38,706 33,101 Total gross accounts receivable $ 42,148 $ 36,104 (1) Rental includes Medicare, Medicaid/other government, private insurance and patient pay. (2) Business-to-business receivables included one customer with a gross accounts receivable balance of $8,978 and $10,695 as of March 31, 2020 and December 31, 2019, respectively. This customer received extended payment terms through a direct financing plan offered. The Company also has a credit insurance policy in place, which allocated up to $20,000 in coverage as of March 31, 2020 and allocated up to $20,000 in coverage as of December 31, 2019 for this customer with a $400 deductible and 10% retention.
Schedule of Net Accounts Receivable Balance Concentrations by Major Category	Net accounts receivable (gross accounts receivable, net of allowances) balance concentrations by major category as of March 31, 2020 and December 31, 2019 were as follows: March 31, December 31, Net accounts receivable 2020 2019 Rental (1) $ 2,912 $ 2,464 Business-to-business and other receivables (2) 37,484 31,861 Total net accounts receivable $ 40,396 $ 34,325 (1) Rental includes Medicare, Medicaid/other government, private insurance and patient pay. (2) Business-to-business receivables included one customer with a gross accounts receivable balance of $8,978 and $10,695 as of March 31, 2020 and December 31, 2019, respectively. This customer received extended payment terms through a direct financing plan offered. The Company also has a credit insurance policy in place, which allocated up to $20,000 in coverage as of March 31, 2020 and allocated up to $20,000 in coverage as of December 31, 2019 for this customer with a $400 deductible and 10% retention.
Schedule of Allowances for Accounts Receivable	The following tables set forth the accounts receivable allowances as of March 31, 2020 and December 31, 2019: March 31, December 31, Allowances - accounts receivable 2020 2019 Doubtful accounts $ 167 $ 205 Rental revenue adjustments 409 411 Sales returns 1,176 1,163 Total allowances - accounts receivable $ 1,752 $ 1,779
Breakdown of Company's Revenue from U.S. and Non-U.S. Sources	A portion of revenue is earned from sales outside the United States. Approximately 68.7% and 72.5% of the non-U.S. revenue for the three months ended March 31, 2020 and March 31, 2019, respectively, were invoiced in Euros. A breakdown of the Company’s revenue from U.S. and non-U.S. sources for the three months ended March 31, 2020 and March 31, 2019, respectively, is as follows: Three months ended March 31, 2020 2019 U.S. revenue $ 68,406 $ 70,399 Non-U.S. revenue 20,083 19,803 Total revenue $ 88,489 $ 90,202
Schedule of Inventories	Inventories that are considered current consist of the following: March 31, December 31, 2020 2019 Raw materials and work-in-progress $ 33,066 $ 31,676 Finished goods 5,931 5,174 Less: reserves (1,397 ) (1,186 ) Inventories, net $ 37,600 $ 35,664
Computation of Depreciation and Amortization using Straight Line Method Over Estimated Useful Lives of Assets	Property and equipment are stated at cost. Depreciation and amortization are calculated using the straight-line method over the assets’ estimated useful lives as follows: Rental equipment 1.5-5 years Manufacturing equipment and tooling 3-5 years Computer equipment and software 2-3 years Furniture and equipment 3-5 years Leasehold improvements Lesser of estimated useful life or remaining lease term
Summary of Depreciation and Amortization Expense of Rental Equipment and Other Property and Equipment	Depreciation and amortization expense related to rental equipment and other property and equipment are summarized below for the three months ended March 31, 2020 and March 31, 2019, respectively. Three months ended March 31, 2020 2019 Rental equipment $ 1,299 $ 1,705 Other property and equipment 921 761 Total depreciation and amortization $ 2,220 $ 2,466
Summary of Property Plant and Equipment and Rental Equipment with Associated Accumulated Depreciation	Property and equipment and rental equipment with associated accumulated depreciation is summarized below as of March 31, 2020 and December 31, 2019, respectively. March 31, December 31, Property and equipment 2020 2019 Rental equipment, net of allowances of $395 and $395, respectively $ 38,995 $ 39,308 Other property and equipment 26,496 24,986 Property and equipment 65,491 64,294 Accumulated depreciation Rental equipment 31,035 30,984 Other property and equipment 14,789 13,872 Accumulated depreciation 45,824 44,856 Property and equipment, net Rental equipment, net of allowances of $395 and $395, respectively 7,960 8,324 Other property and equipment 11,707 11,114 Property and equipment, net $ 19,667 $ 19,438
Schedule of Changes in Carrying Amount of Goodwill	The changes in the carrying amount of goodwill for the three months ended March 31, 2020 were as follows: Balance as of December 31, 2019 $ 32,954 Translation adjustment (42 ) Balance as of March 31, 2020 $ 32,912
Summary of Changes in Net Carrying Values of Intangible Assets	The following tables represent the changes in net carrying values of intangible assets as of the respective dates: Average estimated Gross useful lives carrying Accumulated March 31, 2020 (in years) amount amortization Net amount Technology 10 $ 77,700 $ 4,856 $ 72,844 Licenses 10 185 167 18 Patents and websites 5 4,274 2,479 1,795 Customer relationships 4 1,320 963 357 Commercials 2-3 777 509 268 Total $ 84,256 $ 8,974 $ 75,282 Average estimated Gross useful lives carrying Accumulated December 31, 2019 (in years) amount amortization Net amount Technology 10 $ 77,700 $ 2,914 $ 74,786 Licenses 10 185 165 20 Patents and websites 5 4,274 2,308 1,966 Customer relationships 4 1,346 897 449 Commercials 2-3 777 465 312 Total $ 84,282 $ 6,749 $ 77,533
Schedule of Annual Estimated Amortization Expense	Annual estimated amortization expense for each of the succeeding fiscal years is as follows: March 31, 2020 Remaining 9 months of 2020 $ 6,722 2021 8,678 2022 8,367 2023 7,792 2024 7,787 Thereafter 35,936 $ 75,282
Schedule of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses as of March 31, 2020 and December 31, 2019 consisted of the following: March 31, December 31, 2020 2019 Accounts payable $ 18,727 $ 16,399 Accrued inventory (in-transit and unvouchered receipts) and trade payables 11,129 11,124 Accrued purchasing card liability 1,940 1,675 Accrued franchise, sales and use taxes 501 713 Other accrued expenses 556 819 Accounts payable and accrued expenses $ 32,853 $ 30,730
Schedule of Accrued Payroll	Accrued payroll as of March 31, 2020 and December 31, 2019 consisted of the following: March 31, December 31, 2020 2019 Accrued bonuses $ 1,143 $ 87 Accrued wages and other payroll related items 4,939 3,158 Accrued vacation 2,262 2,169 Accrued employee stock purchase plan deductions 306 801 Accrued payroll $ 8,650 $ 6,215

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Schedule of Right-of-Use Assets and Operating Lease Liabilities	Information related to the Company's right-of-use assets and related operating lease liabilities were as follows: Three months ended March 31, 2020 2019 Cash paid for operating lease liabilities $ 593 $ 576 Operating lease cost 632 544 Non-cash right-of-use assets obtained in exchange for new operating lease obligations 2,809 6,418 Weighted-average remaining lease term 2.5 years 3.1 years Weighted-average discount rate 3.7 % 3.8 %
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities due in the 12-month period ending March 31, 2021 $ 2,205 2022 2,057 2023 1,737 2024 1,725 2025 1,133 Thereafter 3,521 12,378 Less imputed interest (1,399 ) Total lease liabilities $ 10,979 Operating lease liability - current $ 1,863 Operating lease liability - noncurrent $ 9,116 Total lease liabilities $ 10,979

Earnings (Loss) per Share (Tabl

Earnings (Loss) per Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Computation of Earnings (Loss) Per Share	The computation of EPS is as follows: Three months ended March 31, 2020 2019 Numerator—basic and diluted: Net income (loss) $ (1,589 ) $ 5,302 Denominator: Weighted-average common shares - basic common stock (1) 21,916,365 21,750,305 Weighted-average common shares - diluted common stock 21,916,365 22,534,885 Net income (loss) per share - basic common stock $ (0.07 ) $ 0.24 Net income (loss) per share - diluted common stock (2) $ (0.07 ) $ 0.24 Denominator calculation from basic to diluted: Weighted-average common shares - basic common stock (1) 21,916,365 21,750,305 Stock options and other dilutive awards 327,891 784,580 Weighted-average common shares - diluted common stock 22,244,256 22,534,885 Shares excluded from diluted weighted-average shares: Stock options 81,220 — Restricted stock units and restricted stock awards 293,236 119,378 Shares excluded from diluted weighted-average shares 374,456 119,378 (1) Unvested restricted stock units and restricted stock awards are not included as shares outstanding in the calculation of basic earnings (loss) per share. Vested restricted stock units and restricted stock awards are included in basic earnings (loss) per share if all vesting and performance criteria have been met. Performance-based restricted stock units and restricted stock awards are included in the number of shares used to calculate diluted earnings (loss) per share as long as all applicable performance criteria are met, and their effect is dilutive. Restricted stock awards are eligible to receive all dividends declared on the Company’s common shares during the vesting period; however, such dividends are not paid until the restrictions lapse. (2) Due to a net loss for the three months ended March 31, 2020, dilutive loss per share is the same as basic.

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Summary of Stock Options Activity	The activity for stock options under the Company’s stock plans for the three months ended March 31, 2020 is as follows: Remaining weighted- Weighted- average Per share average contractual average Price per exercise terms intrinsic Options share price (in years) value Outstanding as of December 31, 2019 980,884 $0.75-$83.30 $ 35.24 2.84 $ 34.07 Granted — — — Exercised (6,334 ) 1.17-24.52 9.42 Forfeited (1,876 ) 44.19-56.72 52.54 Expired — — — Outstanding as of March 31, 2020 972,674 0.75-83.30 35.38 2.59 18.39 Vested and exercisable as of March 31, 2020 953,431 0.75-83.30 35.20 2.58 18.61 Vested and expected to vest as of March 31, 2020 971,431 $0.75-$83.30 $ 35.37 2.59 $ 18.40
Summary of Restricted Stock Activity	Stock Awards activity for the three months ended March 31, 2020 is summarized below: Weighted- average grant Performance date fair and value Restricted stock units Time-based time-based Total per share Unvested restricted stock units as of December 31, 2019 108,976 3,134 112,110 $ 83.48 Granted 145,413 58,972 204,385 45.78 Vested (10,309 ) — (10,309 ) 107.85 Forfeited/canceled (4,293 ) (3,134 ) (7,427 ) 100.06 Unvested restricted stock units as of March 31, 2020 (1) 239,787 58,972 298,759 $ 56.44 Unvested and expected to vest restricted stock units outstanding as of March 31, 2020 263,337 $ 57.23 Weighted- average grant Performance date fair and value Restricted stock awards Time-based time-based Total per share Unvested restricted stock awards outstanding as of December 31, 2019 71,070 62,628 133,698 $ 95.74 Granted — — — — Vested (8,301 ) — (8,301 ) 108.51 Forfeited/canceled — (29,273 ) (29,273 ) 110.27 Unvested restricted stock awards outstanding as of March 31, 2020 (1) 62,769 33,355 96,124 $ 90.97 Unvested and expected to vest restricted stock awards outstanding as of March 31, 2020 76,815 $ 90.08 (1) Outstanding restricted stock units and restricted stock awards are based on the maximum payout of the targeted number of shares.
Summary of Stock-based Compensation Expense	Stock-based compensation Stock-based compensation expense recognized for the three months ended March 31, 2020 and March 31, 2019, was as follows: Three months ended March 31, 2020 2019 Stock-based compensation expense by type of award: Stock option plan awards $ 525 $ 1,147 Restricted stock units and restricted stock awards 2,083 2,257 Employee stock purchase plan 176 182 Total stock-based compensation expense $ 2,784 $ 3,586 For the three months ended March 31, 2020 and March 31, 2019, respectively, stock-based compensation expense recognized under ASC 718, included in cost of revenue, research and development expense, sales and marketing expense, and general and administrative expense was as follows: Three months ended March 31, 2020 2019 Cost of revenue $ 229 $ 285 Research and development 320 377 Sales and marketing 612 690 General and administrative 1,623 2,234 Total stock-based compensation expense $ 2,784 $ 3,586

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Minimum Aggregate Payments Due under Operating Leases and Specified Non-Cancelable Contractual Obligations Consist of Software License and Maintenance Agreements	The Company enters into non-cancelable contractual obligations for software licenses and maintenance agreements. As of March 31, 2020, the minimum aggregate payments due under specified non-cancelable contractual obligations are summarized as follows: Non-cancelable contractual obligations Remaining 9 months of 2020 $ 433 2021 457 2022 — 2023 — 2024 — Thereafter — $ 890
Schedule of Changes in Aggregate Product Warranty Liabilities	The following table identifies the changes in the Company’s aggregate product warranty liabilities for the three and twelve-month periods ended March 31, 2020 and December 31, 2019, respectively: March 31, December 31, 2020 2019 Product warranty liability at beginning of period $ 12,571 $ 9,530 Accruals for warranties issued 2,650 8,131 Adjustments related to preexisting warranties (including changes in estimates) — 1,433 Settlements made (in cash or in kind) (1,650 ) (6,523 ) Product warranty liability at end of period $ 13,571 $ 12,571

Business Overview - Additional

Business Overview - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020Product
Inogen Europe Holding B.V.
Business Overview Disclosures [Line Items]
Date of incorporation of subsidiary	Apr. 13, 2017
Minimum | Inogen One
Business Overview Disclosures [Line Items]
Number of portable oxygen concentrators	829,000

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020Segment
Accounting Policies [Abstract]
Number of operating segments	1
Number of reportable segments	1

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) - New Aera, Inc.	Aug. 09, 2019USD ($)
Business Acquisition [Line Items]
Cash paid at closing	$ 70,523,000
Maximum
Business Acquisition [Line Items]
Merger consideration	101,923,000
Earnout payment	$ 31,400,000

Acquisitions - Summary of Purch

Acquisitions - Summary of Purchase Price Allocation for Acquisition (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Aug. 09, 2019
Business Acquisition [Line Items]
Goodwill	$ 32,912	$ 32,954
New Aera, Inc.
Business Acquisition [Line Items]
Cash			$ 122
Inventories			140
Other current assets			8
Property and equipment			224
Goodwill			30,742
Intangible assets			77,700
Total assets acquired			108,936
Deferred tax liability - noncurrent			12,664
Earnout liability - noncurrent			25,749
Total liabilities assumed			38,413
Total purchase price			$ 70,523

Acquisitions - Summary of Unaud

Acquisitions - Summary of Unaudited Pro Forma Information (Details) - New Aera, Inc. $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Business Acquisition [Line Items]
Total revenue	$ 90,207
Net income	$ 2,650

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Fair Value Assets Measured on Recurring Basis for Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 208,362	$ 198,037
Fair Value Measurements Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Adjusted cost	208,362	209,086
Gross unrealized gains		8
Fair value	208,362	209,094
Cash and cash equivalents	208,362	198,037
Marketable securities		11,057
Fair Value Measurements Recurring | Cash
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Adjusted cost	50,238	51,560
Fair value	50,238	51,560
Cash and cash equivalents	50,238	51,560
Fair Value Measurements Recurring | Level 1 | Money Market Accounts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Adjusted cost	158,124	146,477
Fair value	158,124	146,477
Cash and cash equivalents	$ 158,124	146,477
Fair Value Measurements Recurring | Level 2 | Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Adjusted cost		2,011
Gross unrealized gains		2
Fair value		2,013
Marketable securities		2,013
Fair Value Measurements Recurring | Level 2 | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Adjusted cost		9,038
Gross unrealized gains		6
Fair value		9,044
Marketable securities		$ 9,044

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Related receivables	$ 40,396,000	$ 34,325,000
Fair Value Measurements Recurring | Level 3 | Maximum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Earnout liability	31,400,000
Forward Contracts
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Related receivables	$ 436,000
Payable		$ 514,000

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 344,621	$ 310,424
Other comprehensive income (loss)	509	136
Ending Balance	347,300	321,894
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	271
Other comprehensive income (loss)	(158)
Ending Balance	113
Unrealized Gains on Marketable Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	6
Other comprehensive income (loss)	(6)
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(364)
Other comprehensive income (loss)	673
Ending Balance	309
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(87)	724
Other comprehensive income (loss)	509	136
Ending Balance	$ 422	$ 860

Fair Value Measurements - Sum_3

Fair Value Measurements - Summary of Quantitative Information about Level 3 Inputs for Fair Value Measurement of Earnout Liability (Details) - Level 3	Mar. 31, 2020	Dec. 31, 2019
Revenue Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earnout liability, measurement input	35	35
WACC
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earnout liability, measurement input	12.50	13
20-Year Risk Free Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earnout liability, measurement input	1.15	2.25
Market Price of Risk
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earnout liability, measurement input	9	10

Fair Value Measurements - Sum_4

Fair Value Measurements - Summary of Reconciliation of Earnout Liability Measured and Carried Fair Value on a Recurring Basis (Details) - Fair Value Measurements Recurring $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning Balance	$ 26,559
Change in fair value	(952)
Ending Balance	$ 25,607

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Cash, Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Cash and cash equivalents
Cash	$ 50,238	$ 51,560
Money market accounts	158,124	146,477
Total cash and cash equivalents	$ 208,362	198,037
Marketable securities
Marketable securities		11,057
Corporate Bonds
Marketable securities
Marketable securities		2,013
U.S. Treasury Securities
Marketable securities
Marketable securities		$ 9,044

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020USD ($)Customer	Mar. 31, 2019USD ($)Customer	Dec. 31, 2019USD ($)
Schedule Of Balance Sheet Components [Line Items]
Unbilled Receivables	$ 596,000		$ 590,000
Accounts receivable, net	$ 40,396,000		34,325,000
Percentage of Non-US revenue invoiced in Euros	68.70%	72.50%
Transfer of inventory to rental equipment	$ 368,000	$ 441,000
Salvage value of expenditures for additions, improvements and replacements	0
Repairs and maintenance expense	524,000	662,000
Depreciation and amortization	2,220,000	2,466,000
Impairments of long-lived assets	0	0
Impairment of finite lived intangible assets	0	0
Amortization of intangible assets	2,242,000	328,000
Construction in Process and Computer Software or Development Cost
Schedule Of Balance Sheet Components [Line Items]
Depreciation and amortization	0	$ 0
Other Noncurrent Assets
Schedule Of Balance Sheet Components [Line Items]
Noncurrent inventories expected to be realized or consumed	2,150,000		1,076,000
Customer Concentration Risk | Customer One
Schedule Of Balance Sheet Components [Line Items]
Accounts receivable, net	10,341,000		10,695,000
Customer Concentration Risk | Customer Two
Schedule Of Balance Sheet Components [Line Items]
Accounts receivable, net	$ 8,978,000		$ 5,228,000
Sales Revenue, Net | Customer Concentration Risk
Schedule Of Balance Sheet Components [Line Items]
Number of customers | Customer	1	0
Net Accounts Receivable | Customer Concentration Risk
Schedule Of Balance Sheet Components [Line Items]
Number of customers | Customer	2
Raw materials | Supplier Concentration Risk | Vendor one
Schedule Of Balance Sheet Components [Line Items]
Concentration risk, percentage	23.60%	20.60%
Raw materials | Supplier Concentration Risk | Vendor two
Schedule Of Balance Sheet Components [Line Items]
Concentration risk, percentage	15.20%	11.60%
Raw materials | Supplier Concentration Risk | Vendor three
Schedule Of Balance Sheet Components [Line Items]
Concentration risk, percentage	9.40%	11.40%

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Gross Accounts Receivable Balance Concentrations by Major Category (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accounts Notes And Loans Receivable [Line Items]
Gross accounts receivable	$ 42,148	$ 36,104
Rental
Accounts Notes And Loans Receivable [Line Items]
Gross accounts receivable	3,442	3,003
Business To Business And Other Receivables
Accounts Notes And Loans Receivable [Line Items]
Gross accounts receivable	$ 38,706	$ 33,101

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Net Accounts Receivable Balance Concentrations by Major Category (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accounts Notes And Loans Receivable [Line Items]
Net accounts receivable	$ 40,396	$ 34,325
Rental
Accounts Notes And Loans Receivable [Line Items]
Net accounts receivable	2,912	2,464
Business To Business And Other Receivables
Accounts Notes And Loans Receivable [Line Items]
Net accounts receivable	$ 37,484	$ 31,861

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Net Accounts Receivable Balance Concentrations by Major Category (Parenthetical) (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2020USD ($)Customer	Dec. 31, 2019USD ($)Customer
Accounts Notes And Loans Receivable [Line Items]
Gross accounts receivable	$ 42,148,000	$ 36,104,000
Customer Concentration Risk | Business To Business Receivables
Accounts Notes And Loans Receivable [Line Items]
Number of customers | Customer	1	1
Gross accounts receivable	$ 8,978,000	$ 10,695,000
Credit insurance policy, deductible amount	$ 400,000
Credit insurance policy, retention percentage	10.00%
Customer Concentration Risk | Business To Business Receivables | Maximum
Accounts Notes And Loans Receivable [Line Items]
Credit insurance policy, coverage limit	$ 20,000,000	$ 20,000,000

Balance Sheet Components - Sc_4

Balance Sheet Components - Schedule of Allowances for Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Allowances - accounts receivable
Doubtful accounts	$ 167	$ 205
Rental revenue adjustments	409	411
Sales returns	1,176	1,163
Total allowances - accounts receivable	$ 1,752	$ 1,779

Balance Sheet Components - Brea

Balance Sheet Components - Breakdown of the Company Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Concentration Risk [Line Items]
Revenues	$ 88,489	$ 90,202
U.S. revenue
Concentration Risk [Line Items]
Revenues	68,406	70,399
Non-U.S. revenue
Concentration Risk [Line Items]
Revenues	$ 20,083	$ 19,803

Balance Sheet Components - Sc_5

Balance Sheet Components - Schedule of Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials and work-in-progress	$ 33,066	$ 31,676
Finished goods	5,931	5,174
Less: reserves	(1,397)	(1,186)
Inventories, net	$ 37,600	$ 35,664

Balance Sheet Components - Comp

Balance Sheet Components - Computation of Depreciation and Amortization Using Straight Line Method Over Estimated Useful Lives of Assets (Details)	3 Months Ended
	Mar. 31, 2020
Rental equipment | Minimum
Property Plant And Equipment [Line Items]
Property Plant And Equipment Useful Life	1 year 6 months
Rental equipment | Maximum
Property Plant And Equipment [Line Items]
Property Plant And Equipment Useful Life	5 years
Manufacturing equipment and tooling | Minimum
Property Plant And Equipment [Line Items]
Property Plant And Equipment Useful Life	3 years
Manufacturing equipment and tooling | Maximum
Property Plant And Equipment [Line Items]
Property Plant And Equipment Useful Life	5 years
Computer equipment and software | Minimum
Property Plant And Equipment [Line Items]
Property Plant And Equipment Useful Life	2 years
Computer equipment and software | Maximum
Property Plant And Equipment [Line Items]
Property Plant And Equipment Useful Life	3 years
Furniture and equipment | Minimum
Property Plant And Equipment [Line Items]
Property Plant And Equipment Useful Life	3 years
Furniture and equipment | Maximum
Property Plant And Equipment [Line Items]
Property Plant And Equipment Useful Life	5 years
Leasehold improvements
Property Plant And Equipment [Line Items]
Property Plant And Equipment Useful Life	Lesser of estimated useful life or remaining lease term

Balance Sheet Components - Su_2

Balance Sheet Components - Summary of Depreciation and Amortization Expense of Rental Equipment and Other Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Property Plant And Equipment [Line Items]
Depreciation	$ 1,299	$ 1,705
Depreciation and amortization	2,220	2,466
Rental equipment
Property Plant And Equipment [Line Items]
Depreciation	1,299	1,705
Other property and equipment
Property Plant And Equipment [Line Items]
Depreciation and amortization	$ 921	$ 761

Balance Sheet Components - Su_3

Balance Sheet Components - Summary of Property Plant and Equipment and Rental Equipment with Associated Accumulated Depreciation (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment	$ 65,491	$ 64,294
Accumulated depreciation	45,824	44,856
Property and equipment, net	19,667	19,438
Rental equipment
Property Plant And Equipment [Line Items]
Property and equipment	38,995	39,308
Accumulated depreciation	31,035	30,984
Property and equipment, net	7,960	8,324
Other property and equipment
Property Plant And Equipment [Line Items]
Property and equipment	26,496	24,986
Accumulated depreciation	14,789	13,872
Property and equipment, net	$ 11,707	$ 11,114

Balance Sheet Components - Su_4

Balance Sheet Components - Summary of Property Plant and Equipment and Rental Equipment with Associated Accumulated Depreciation (Parenthetical) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Abstract]
Rental equipment, allowance	$ 395	$ 395

Balance Sheet Components - Sc_6

Balance Sheet Components - Schedule of Changes in Carrying Amount of Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
Balance as of December 31, 2019	$ 32,954
Translation adjustment	(42)
Balance as of March 31, 2020	$ 32,912

Balance Sheet Components - Su_5

Balance Sheet Components - Summary of Changes in Net Carrying Values of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 84,256	$ 84,282
Accumulated amortization	8,974	6,749
Net amount	$ 75,282	$ 77,533
Technology
Finite Lived Intangible Assets [Line Items]
Average estimated useful lives (in years)	10 years	10 years
Gross carrying amount	$ 77,700	$ 77,700
Accumulated amortization	4,856	2,914
Net amount	$ 72,844	$ 74,786
Licenses
Finite Lived Intangible Assets [Line Items]
Average estimated useful lives (in years)	10 years	10 years
Gross carrying amount	$ 185	$ 185
Accumulated amortization	167	165
Net amount	$ 18	$ 20
Patents And Websites
Finite Lived Intangible Assets [Line Items]
Average estimated useful lives (in years)	5 years	5 years
Gross carrying amount	$ 4,274	$ 4,274
Accumulated amortization	2,479	2,308
Net amount	$ 1,795	$ 1,966
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Average estimated useful lives (in years)	4 years	4 years
Gross carrying amount	$ 1,320	$ 1,346
Accumulated amortization	963	897
Net amount	357	449
Commercials
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	777	777
Accumulated amortization	509	465
Net amount	$ 268	$ 312
Commercials | Minimum
Finite Lived Intangible Assets [Line Items]
Average estimated useful lives (in years)	2 years	2 years
Commercials | Maximum
Finite Lived Intangible Assets [Line Items]
Average estimated useful lives (in years)	3 years	3 years

Balance Sheet Components - Sc_7

Balance Sheet Components - Schedule of Annual Estimated Amortization Expense (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Remaining 9 months of 2020	$ 6,722
2021	8,678
2022	8,367
2023	7,792
2024	7,787
Thereafter	35,936
Net amount	$ 75,282	$ 77,533

Balance Sheet Components - Sc_8

Balance Sheet Components - Schedule of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accounts payable	$ 18,727	$ 16,399
Accrued inventory (in-transit and unvouchered receipts) and trade payables	11,129	11,124
Accrued purchasing card liability	1,940	1,675
Accrued franchise, sales and use taxes	501	713
Other accrued expenses	556	819
Accounts payable and accrued expenses	$ 32,853	$ 30,730

Balance Sheet Components - Sc_9

Balance Sheet Components - Schedule of Accrued Payroll (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued bonuses	$ 1,143	$ 87
Accrued wages and other payroll related items	4,939	3,158
Accrued vacation	2,262	2,169
Accrued employee stock purchase plan deductions	306	801
Accrued payroll	$ 8,650	$ 6,215

Leases - Additional Information

Leases - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Lessee Lease Description [Line Items]
Operating lease, option to extend	options to extend the leases for up to 5 years.
Operating lease, existence of option to extend [true false]	true
Operating lease cost	$ 632,000	$ 544,000
Corporate Headquarters in California
Lessee Lease Description [Line Items]
Annual percentage increase in rental expense	3.50%
Lease payments annual increase description	Lease payments for its corporate headquarters will increase annually by the lesser of the change, if any, in the Consumer Price Index of the Bureau of Labor Statistics of the U.S. Department of Labor or three and one-half percent (3.5%) at each annual adjustment date thereafter.
Industrial Space in Texas
Lessee Lease Description [Line Items]
Annual percentage increase in rental expense	2.50%
Lease payments annual increase description	Lease payments for the Company’s industrial space in Texas will increase annually by two and one-half percent (2.5%) at each annual adjustment date thereafter
Property owned by a related party
Lessee Lease Description [Line Items]
Operating lease cost	$ 8,000
Minimum
Lessee Lease Description [Line Items]
Operating leases, lease term	2 years
Minimum | Corporate Headquarters in California and Industrial Space in Texas
Lessee Lease Description [Line Items]
Operating leases, lease term	10 years
Additional operating lease cost	$ 21,548,000
Maximum
Lessee Lease Description [Line Items]
Operating leases, lease term	8 years
Operating lease option to extend term	5 years
Maximum | Corporate Headquarters in California and Industrial Space in Texas
Lessee Lease Description [Line Items]
Operating leases, lease term	11 years

Leases - Schedule of Right-of-U

Leases - Schedule of Right-of-Use Assets and Operating Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Leases [Abstract]
Cash paid for operating lease liabilities	$ 593	$ 576
Operating lease cost	632	544
Non-cash right-of-use assets obtained in exchange for new operating lease obligations	$ 2,809	$ 6,418
Weighted-average remaining lease term	2 years 6 months	3 years 1 month 6 days
Weighted-average discount rate	3.70%	3.80%

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Maturities of lease liabilities due in the 12-month period ending March 31,
2021	$ 2,205
2022	2,057
2023	1,737
2024	1,725
2025	1,133
Thereafter	3,521
Operating lease liabilities payments due	12,378
Less imputed interest	(1,399)
Total lease liabilities	10,979
Operating lease liability - current	1,863	$ 2,014
Operating lease liability - noncurrent	9,116	$ 4,702
Total lease liabilities	$ 10,979

Earnings (Loss) per Share - Com

Earnings (Loss) per Share - Computation of Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator—basic and diluted:
Net income (loss)	$ (1,589)	$ 5,302
Denominator:
Weighted-average common shares - basic common stock	21,916,365	21,750,305
Weighted-average common shares - diluted common stock	21,916,365	22,534,885
Net income (loss) per share - basic common stock	$ (0.07)	$ 0.24
Net income (loss) per share - diluted common stock	$ (0.07)	$ 0.24
Denominator calculation from basic to diluted:
Weighted-average common shares - basic common stock	21,916,365	21,750,305
Stock options and other dilutive awards	327,891	784,580
Weighted-average common shares - diluted common stock	22,244,256	22,534,885
Shares excluded from diluted weighted-average shares:
Shares excluded from diluted weighted-average shares	374,456	119,378
Stock options
Shares excluded from diluted weighted-average shares:
Shares excluded from diluted weighted-average shares	81,220
Restricted stock units and restricted stock awards
Shares excluded from diluted weighted-average shares:
Shares excluded from diluted weighted-average shares	293,236	119,378

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, interest or penalties recognized	$ 0	$ 0

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Class Of Stock [Line Items]
Total intrinsic value of options exercised	$ 239	$ 6,733
Stock-based compensation, unrecognized expense, nonvested granted awards	163
401(k) Retirement Savings Plan
Class Of Stock [Line Items]
Defined benefit plan, contributed by employer net of forfeitures	$ 252	$ 318
Stock options
Class Of Stock [Line Items]
Amount expected to recognized over weighted-average period	1 month 6 days
Rate of reduced stock-based compensation expense for estimated forfeiture	7.30%	7.30%
Time based restricted stock units
Class Of Stock [Line Items]
Vesting period	4 years
Time based restricted stock awards
Class Of Stock [Line Items]
Vesting period	4 years
Performance and time based restricted stock awards
Class Of Stock [Line Items]
Vesting period	3 years
Performance and time based restricted stock units
Class Of Stock [Line Items]
Vesting period	3 years
Restricted stock units and restricted stock awards
Class Of Stock [Line Items]
Amount expected to recognized over weighted-average period	2 years 10 months 24 days
Unrecognized compensation cost related to unvested employee excluding estimated forfeitures	$ 18,992
Maximum | Stock options
Class Of Stock [Line Items]
Stock option period, expiration	10 years
Vesting period	4 years
Minimum | Stock options
Class Of Stock [Line Items]
Stock option period, expiration	7 years
Vesting period	1 year
2002 Plan
Class Of Stock [Line Items]
Stock option shares outstanding	333
Number of equity awards available for grant	0
2012 Plan
Class Of Stock [Line Items]
Stock option shares outstanding	138,736
Number of equity awards available for grant	0
2014 Plan
Class Of Stock [Line Items]
Stock option shares outstanding	1,217,373
Number of equity awards available for grant	1,643,970
Terms of shares available for issuance	The number of shares available for issuance under the 2014 Plan also is increased annually on the first day of each fiscal year equal to the least of: 895,346 shares; 4% of the outstanding shares of common stock as of the last day of the Company's immediately preceding fiscal year; or such other amount as the Company's board of directors may determine.
Common stock capital shares reserved for future issuance maximum annual increase	895,346
Percentage on outstanding shares of common stock	4.00%
Number of additional number of shares reserve to provision	0
2012 Plan and 2002 Plan | Maximum
Class Of Stock [Line Items]
Stock option shares outstanding	2,328,569
2014 ESPP Plan
Class Of Stock [Line Items]
Number of equity awards available for grant	670,678
Terms of shares available for issuance	The number of shares available for sale under the ESPP is increased annually on the first day of each fiscal year equal to the least of: 179,069 shares; 1.5% of the outstanding shares of the Company's common stock on the last day of the Company's immediately preceding fiscal year; or such other amount as may be determined by the administrator.
Percentage on outstanding shares of common stock	1.50%
Number of additional number of shares reserve to provision	0
Maximum percentage of common stock eligible to purchase through payroll deductions for participants	15.00%
Maximum number of shares available for participant to purchase during period	1,500
Purchase price as percentage of stock price on offering period	85.00%
Purchase price as percentage of stock price on exercise date	85.00%
Potential increase of shares available for issuance	179,069

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Options Activity (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Stock Options Outstanding, Beginning balance	980,884
Stock Options, Exercised	(6,334)
Stock Options, Forfeited	(1,876)
Stock Options Outstanding, Ending balance	972,674	980,884
Stock Options, Vested and exercisable	953,431
Stock Options, Vested and expected to vest	971,431
Outstanding, Weighted-average exercise price, Beginning balance	$ 35.24
Weighted-average exercise price, Exercised	9.42
Weighted-average exercise price, Forfeited	52.54
Outstanding, Weighted-average exercise price, Ending balance	35.38	$ 35.24
Weighted-average exercise price, Vested and exercisable	35.20
Weighted-average exercise price, Vested and expected to vest	$ 35.37
Remaining weighted-average contractual term, Outstanding	2 years 7 months 2 days	2 years 10 months 2 days
Remaining weighted-average contractual term, Vested and exercisable	2 years 6 months 29 days
Remaining weighted-average contractual term, Vested and expected to vest	2 years 7 months 2 days
Outstanding, Per share average intrinsic value	$ 18.39	$ 34.07
Per share average intrinsic value, Vested and exercisable	18.61
Per share average intrinsic value, Vested and expected to vest	18.40
Minimum
Class Of Stock [Line Items]
Outstanding, Price per share, Beginning balance	0.75
Price per share, Exercised	1.17
Price per share, Forfeited	44.19
Outstanding, Price per share, Ending balance	0.75	0.75
Price per share, Vested and exercisable	0.75
Price per share, Vested and expected to vest	0.75
Maximum
Class Of Stock [Line Items]
Outstanding, Price per share, Beginning balance	83.30
Price per share, Exercised	24.52
Price per share, Forfeited	56.72
Outstanding, Price per share, Ending balance	83.30	$ 83.30
Price per share, Vested and exercisable	83.30
Price per share, Vested and expected to vest	$ 83.30

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Restricted Stock Activity (Details)	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Time based restricted stock units
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	108,976
Granted	145,413
Vested	(10,309)
Forfeited/canceled	(4,293)
Unvested restricted stock units/ awards outstanding, Ending balance	239,787
Performance and time based restricted stock units
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	3,134
Granted	58,972
Forfeited/canceled	(3,134)
Unvested restricted stock units/ awards outstanding, Ending balance	58,972
Restricted stock units
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	112,110
Granted	204,385
Vested	(10,309)
Forfeited/canceled	(7,427)
Unvested restricted stock units/ awards outstanding, Ending balance	298,759
Unvested and expected to vest restricted stock units/awards outstanding	263,337
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Beginning balance | $ / shares	$ 83.48
Weighted-average grant date fair value per share, Granted | $ / shares	45.78
Weighted-average grant date fair value per share, Vested | $ / shares	107.85
Weighted-average grant date fair value per share, Forfeited/canceled | $ / shares	100.06
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Ending balance | $ / shares	56.44
Weighted-average grant date fair value per share, Unvested and expected to vest restricted stock units/awards outstanding | $ / shares	$ 57.23
Time based restricted stock awards
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	71,070
Vested	(8,301)
Unvested restricted stock units/ awards outstanding, Ending balance	62,769
Performance and time based restricted stock awards
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	62,628
Forfeited/canceled	(29,273)
Unvested restricted stock units/ awards outstanding, Ending balance	33,355
Restricted stock awards
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	133,698
Vested	(8,301)
Forfeited/canceled	(29,273)
Unvested restricted stock units/ awards outstanding, Ending balance	96,124
Unvested and expected to vest restricted stock units/awards outstanding	76,815
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Beginning balance | $ / shares	$ 95.74
Weighted-average grant date fair value per share, Vested | $ / shares	108.51
Weighted-average grant date fair value per share, Forfeited/canceled | $ / shares	110.27
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Ending balance | $ / shares	90.97
Weighted-average grant date fair value per share, Unvested and expected to vest restricted stock units/awards outstanding | $ / shares	$ 90.08

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Stock-based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Stock-based compensation expense by type of award:
Stock-based compensation expense	$ 2,784	$ 3,586
Stock Option Plan Awards
Stock-based compensation expense by type of award:
Stock-based compensation expense	525	1,147
Restricted stock units and restricted stock awards
Stock-based compensation expense by type of award:
Stock-based compensation expense	2,083	2,257
Employee Stock Purchase Plan
Stock-based compensation expense by type of award:
Stock-based compensation expense	$ 176	$ 182

Stockholders' Equity - Summar_4

Stockholders' Equity - Summary of Stock-based Compensation Expense Recognized in Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Class Of Stock [Line Items]
Stock-based compensation expense	$ 2,784	$ 3,586
Cost of Revenue
Class Of Stock [Line Items]
Stock-based compensation expense	229	285
Research and Development
Class Of Stock [Line Items]
Stock-based compensation expense	320	377
Sales and Marketing
Class Of Stock [Line Items]
Stock-based compensation expense	612	690
General and Administrative
Class Of Stock [Line Items]
Stock-based compensation expense	$ 1,623	$ 2,234

Commitments and Contingencies -

Commitments and Contingencies - Minimum Aggregate Payments Due under Operating Leases and Specified Non-Cancelable Contractual Obligations Consist of Software License and Maintenance Agreements (Details) $ in Thousands	Mar. 31, 2020USD ($)
Commitments And Contingencies Disclosure [Abstract]
Non-cancelable contractual obligations, Remaining 9 months of 2020	$ 433
Non-cancelable contractual obligations, 2021	457
Non-cancelable contractual obligations, Total minimum payments	$ 890

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Oct. 31, 2019Lawsuit	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Jan. 13, 2020Lawsuit	May 20, 2019Lawsuit
Commitments And Contingencies [Line Items]
Outstanding purchase orders with its outside vendors and suppliers		$ 61,400
Payments received in advance of satisfying performance obligations		1,648
Performance obligation partially offset of revenue recognized		1,289
Number of lawsuits | Lawsuit					2
No. of additional shareholder derivative who filed lawsuits | Lawsuit	3
Number of derivative lawsuits | Lawsuit				4
Lifetime Warranties | Direct-to-Consumer
Commitments And Contingencies [Line Items]
Sales revenue		$ 18,087	$ 17,728

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Changes in Aggregate Product Warranty Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Product warranty liability at beginning of period	$ 12,571	$ 9,530
Accruals for warranties issued	2,650	8,131
Adjustments related to preexisting warranties (including changes in estimates)		1,433
Settlements made (in cash or in kind)	(1,650)	(6,523)
Product warranty liability at end of period	$ 13,571	$ 12,571

Foreign Currency Exchange Con_2

Foreign Currency Exchange Contracts and Hedging - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020USD ($)Contract	Mar. 31, 2019USD ($)Contract
Derivatives Fair Value [Line Items]
Number of contract designated hedges | Contract	8	22
Number of contract non-designated hedges | Contract	1	3
Non-Designated Derivative Contracts
Derivatives Fair Value [Line Items]
Derivative contracts notional amounts	$ 3,885,000	$ 2,369,000
Designated Derivative Contracts
Derivatives Fair Value [Line Items]
Derivative contracts notional amounts	23,788,000	16,072,000
Unrealized gain on derivative	$ 673,000	$ 260,000
Minimum
Derivatives Fair Value [Line Items]
Derivative contracts expiration period	1 month
Maximum
Derivatives Fair Value [Line Items]
Derivative contracts expiration period	9 months