Inogen (INGN) 10-K 25 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Feb. 21, 2020	Jun. 30, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	INGN
Entity Registrant Name	INOGEN, INC.
Entity Central Index Key	0001294133
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		22,033,576
Entity Public Float			$ 811.4
Document Annual 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
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant’s definitive Proxy Statement to be filed with the Securities and Exchange Commission in connection with the registrant’s 2020 Annual Meeting of Stockholders, which will be filed subsequent to the date hereof, are incorporated by reference into Part III of this Form 10-K. Such Proxy Statement will be filed with the Securities and Exchange Commission not later than 120 days following the end of the registrant’s fiscal year ended December 31, 2019.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 198,037	$ 196,634
Marketable securities	11,057	43,715
Accounts receivable, net	34,325	37,041
Inventories, net	35,664	27,071
Income tax receivable	2,976	2,655
Prepaid expenses and other current assets	10,160	7,467
Total current assets	292,219	314,583
Property and equipment
Rental equipment, net	39,308	43,038
Manufacturing equipment and tooling	9,704	7,338
Computer equipment and software	7,266	6,153
Furniture and equipment	1,730	1,445
Leasehold improvements	4,388	3,407
Land and building	125	125
Construction in process	1,773	3,128
Total property and equipment	64,294	64,634
Less accumulated depreciation	(44,856)	(42,293)
Property and equipment, net	19,438	22,341
Goodwill	32,954	2,257
Intangible assets, net	77,533	3,755
Operating lease right-of-use asset	5,855
Deferred tax asset - noncurrent	14,452	30,130
Other assets	4,888	2,832
Total assets	447,339	375,898
Current liabilities
Accounts payable and accrued expenses	30,730	26,786
Accrued payroll	6,215	11,407
Warranty reserve - current	4,923	3,549
Operating lease liability - current	2,014
Deferred revenue - current	5,478	4,451
Income tax payable	821	392
Total current liabilities	50,181	46,585
Long-term liabilities
Warranty reserve - noncurrent	7,648	5,981
Operating lease liability - noncurrent	4,702
Earnout liability - noncurrent	26,559
Deferred revenue - noncurrent	13,541	11,844
Deferred tax liability - noncurrent	87	232
Other noncurrent liabilities		832
Total liabilities	102,718	65,474
Commitments and contingencies (Note 9)
Stockholders' equity
Common stock, $0.001 par value per share; 200,000,000 shares authorized; 22,031,410 and 21,778,632 shares issued and outstanding as of December 31, 2019 and 2018, respectively	22	22
Additional paid-in capital	263,252	249,194
Retained earnings	81,434	60,484
Accumulated other comprehensive income (loss)	(87)	724
Total stockholders' equity	344,621	310,424
Total liabilities and stockholders' equity	$ 447,339	$ 375,898

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
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	22,031,410	21,778,632
Common stock, shares outstanding	22,031,410	21,778,632

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue
Sales revenue	$ 340,546	$ 336,015	$ 225,492
Rental revenue	21,397	22,096	23,946
Total revenue	361,943	358,111	249,438
Cost of revenue
Cost of sales revenue	175,974	163,989	110,163
Cost of rental revenue, including depreciation of $6,253, $7,567 and $9,835, respectively	14,108	15,542	18,038
Total cost of revenue	190,082	179,531	128,201
Gross profit
Gross profit-sales revenue	164,572	172,026	115,329
Gross profit-rental revenue	7,289	6,554	5,908
Total gross profit	171,861	178,580	121,237
Operating expense
Research and development	9,401	7,029	5,313
Sales and marketing	105,550	95,641	50,758
General and administrative	37,121	38,018	37,576
Total operating expense	152,072	140,688	93,647
Income from operations	19,789	37,892	27,590
Other income (expense)
Interest income	4,712	3,259	765
Other income (expense)	(229)	(696)	1,301
Total other income, net	4,483	2,563	2,066
Income before provision (benefit) for income taxes	24,272	40,455	29,656
Provision (benefit) for income taxes	3,322	(11,390)	8,654
Net income	20,950	51,845	21,002
Other comprehensive income (loss), net of tax
Change in foreign currency translation adjustment	(123)	31	363
Change in net unrealized gains (losses) on foreign currency hedging	(1,566)	981	(567)
Less: reclassification adjustment for net (gains) losses included in net income	872	(577)	446
Total net change in unrealized gains (losses) on foreign currency hedging	(694)	404	(121)
Change in net unrealized gains (losses) on marketable securities	6	17	65
Total other comprehensive income (loss), net of tax	(811)	452	307
Comprehensive income	$ 20,139	$ 52,297	$ 21,309
Basic net income per share attributable to common stockholders (Note 2)	$ 0.96	$ 2.44	$ 1.02
Diluted net income per share attributable to common stockholders (Note 2)	$ 0.94	$ 2.30	$ 0.96
Weighted-average number of shares used in calculating net income per share attributable to common stockholders:
Basic common shares	21,821,104	21,266,696	20,683,807
Diluted common shares	22,241,064	22,514,513	21,897,988

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Depreciation	$ 6,253	$ 7,567	$ 9,835

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings (accumulated deficit)	Accumulated other comprehensive income (loss)
Beginning Balance at Dec. 31, 2016	$ 182,088	$ 20	$ 194,466	$ (12,363)	$ (35)
Beginning Balance at Dec. 31, 2016		20,389,860
Stock-based compensation	9,640		9,640
Employee stock purchases	1,379		1,379
Employee stock purchases, shares		24,523
Stock options exercised	$ 12,625	$ 1	12,624
Stock options exercised, shares	520,393	561,967
Net income	$ 21,002			21,002
Other comprehensive income (loss)	307				307
Ending Balance at Dec. 31, 2017	227,041	$ 21	218,109	8,639	272
Ending Balance at Dec. 31, 2017		20,976,350
Stock-based compensation	12,790		12,790
Employee stock purchases	2,348		2,348
Employee stock purchases, shares		25,532
Restricted stock awards issued, net of forfeitures, shares		56,609
Vesting of restricted stock units, shares		18,112
Shares withheld related to net restricted stock settlement	(1,208)		(1,208)
Shares withheld related to net restricted stock settlement, shares		(6,290)
Stock options exercised	$ 17,156	$ 1	17,155
Stock options exercised, shares	708,319	708,319
Net income	$ 51,845			51,845
Other comprehensive income (loss)	452				452
Ending Balance at Dec. 31, 2018	310,424	$ 22	249,194	60,484	724
Ending Balance at Dec. 31, 2018		21,778,632
Stock-based compensation	9,129		9,129
Employee stock purchases	2,748		2,748
Employee stock purchases, shares		47,816
Restricted stock awards issued, net of forfeitures, shares		82,677
Vesting of restricted stock units	(82)		(82)
Vesting of restricted stock units, shares		28,115
Shares withheld related to net restricted stock settlement	(846)		(846)
Shares withheld related to net restricted stock settlement, shares		(15,121)
Stock options exercised	$ 3,109		3,109
Stock options exercised, shares	109,291	109,291
Net income	$ 20,950			20,950
Other comprehensive income (loss)	(811)				(811)
Ending Balance at Dec. 31, 2019	$ 344,621	$ 22	$ 263,252	$ 81,434	$ (87)
Ending Balance at Dec. 31, 2019		22,031,410

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income	$ 20,950	$ 51,845	$ 21,002
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	13,834	11,295	12,302
Loss on rental assets and other fixed assets	568	1,160	1,136
Gain on sale of former rental assets	(68)	(416)	(64)
Provision for sales revenue returns and doubtful accounts	17,177	17,518	13,773
Provision for rental revenue adjustments	2,233	2,678	5,057
Provision for inventory losses	972	351	340
Stock-based compensation expense	9,129	12,790	9,640
Deferred income taxes	2,873	(11,595)	7,947
Change in fair value of earnout liability	810
Changes in operating assets and liabilities:
Accounts receivable	(16,707)	(25,963)	(18,263)
Inventories	(10,336)	(9,972)	(5,894)
Income tax receivable	(321)	(1,348)	(875)
Prepaid expenses and other current assets	(2,693)	(4,524)	(782)
Operating lease right-of-use asset	(5,856)
Other noncurrent assets	(2,064)	(1,626)
Accounts payable and accrued expenses	3,202	6,360	7,438
Accrued payroll	(5,188)	4,538	722
Warranty reserve	3,041	3,359	2,689
Deferred revenue	2,724	3,360	3,654
Income tax payable	429	64	225
Operating lease liability	6,716
Other noncurrent liabilities	(832)	103	447
Net cash provided by operating activities	40,593	59,977	60,494
Cash flows from investing activities
Purchases of marketable securities	(58,686)	(76,162)	(46,933)
Maturities of marketable securities	91,350	63,455	37,041
Investment in intangible assets	(254)	(350)	(3,316)
Investment in property and equipment	(3,143)	(8,043)	(2,914)
Production and purchase of rental equipment	(3,117)	(4,580)	(3,997)
Proceeds from sale of former assets	194	715	183
Payment for acquisition, net of cash acquired	(70,401)		(4,494)
Net cash used in investing activities	(44,057)	(24,965)	(24,430)
Cash flows from financing activities
Proceeds from stock options exercised	3,109	17,156	12,625
Proceeds from employee stock purchases	2,748	2,348	1,379
Payment of employment taxes related to release of restricted stock	(928)	(1,208)
Net cash provided by financing activities	4,929	18,296	14,004
Effect of exchange rates on cash	(62)	373	34
Net increase in cash and cash equivalents	1,403	53,681	50,102
Cash and cash equivalents, beginning of period	196,634	142,953	92,851
Cash and cash equivalents, end of period	198,037	196,634	142,953
Supplemental disclosures of cash flow information
Cash paid during the period for income taxes, net of refunds received	239	1,653	1,267
Supplemental disclosure of non-cash transactions
Accrued value of earnout related to acquisition	25,749
Property and equipment in account payable and accrued liabilities	$ 66	$ 125	$ 70

Nature of Business

Nature of Business	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Business	1. Nature of business 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 774,000 of its Inogen oxygen concentrators as of December 31, 2019. 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of significant accounting policies Basis of presentation 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). Basis of consolidation The consolidated financial statements include the accounts of Inogen, Inc. and its wholly owned subsidiary. All intercompany balances and transactions have been eliminated. Accounting 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. Revenue The Company generates revenue primarily from sales and rentals of its products. The Company’s products consist of its proprietary line of oxygen concentrators, non-invasive ventilators, and related accessories. Other revenue, which is included in sales revenue on the Statements of Comprehensive Income, primarily comes from service contracts, replacement parts and freight revenue for product shipments. Sales revenue Revenue is recognized upon transfer of control of promised products or services to customers in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. Revenue from product sales is generally recognized upon shipment of the product but is deferred for certain transactions when control has not yet transferred to the customer. The Company’s product is generally sold with a right of return and the Company may provide other incentives, which are accounted for as variable consideration when estimating the amount of revenue to recognize. Returns and incentives are estimated at the time sales revenue is recognized. The provision for estimated returns is calculated based on historical data and future expectations. Sales revenue incentives within the Company’s contracts are estimated based on the most likely amounts expected on the related sales transactions and recorded as a reduction to revenue at the time of sale in accordance with the terms of the contract. The Company also offers a lifetime warranty for direct-to-consumer sales of its oxygen concentrators. For a fixed price, the Company agrees to provide a fully functional oxygen concentrator for the remaining life of the patient. Lifetime warranties are only offered to patients upon the initial sale of oxygen concentrators directly from the Company and are non-transferable. Lifetime warranties are considered to be a distinct performance obligation that are accounted for separately from its sale of oxygen concentrators with a standard warranty of three years . The revenue is allocated to the distinct lifetime warranty performance obligation based on a relative SSP method. The Company has vendor-specific objective evidence of the selling price for its equipment. To determine the selling price of the lifetime warranty, the Company uses its best estimate of the SSP for the distinct performance obligation as the lifetime warranty is neither separately priced nor is the selling price available through third-party evidence. To calculate the selling price associated with the lifetime warranties, management considers the profit margins of service revenue, the average estimated cost of lifetime warranties and the price of extended warranties. Revenue from the distinct lifetime warranty is deferred after the delivery of the equipment and recognized based on an estimated mortality rate over five years, which is the estimated performance period of the contract based on the average patient life expectancy. Revenue from the sale of the Company’s repair services is recognized when the performance obligations are satisfied and collection of the receivables is probable. Other revenue from the sale of replacement parts is generally recognized when product is shipped to customers. Freight revenue consists of fees associated with the deployment of products internationally and domestically when expedited freight options are requested or when minimum order quantities are not met. Freight revenue is generally recognized upon shipment of the product but is deferred if control has not yet transferred to the customer. Shipping and handling costs for sold products and rental assets shipped to the Company’s customers are included on the consolidated statements of comprehensive income as part of cost of sales revenue and cost of rental revenue, respectively. The payment terms and conditions of customer contracts vary by customer type and the products and services offered. For certain products or services and customer types, the Company requires payment before the products or services are delivered to the customer. The timing of sales revenue recognition, billing and cash collection results in billed accounts receivable and deferred revenue in the consolidated balance sheet. Contract liabilities primarily consist of deferred revenue related to lifetime warranties on direct-to-consumer sales revenue when cash 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 years ended December 31, 2019 and December 31, 2018 was primarily driven by $8,757 and $6,909, respectively, of payments received in advance of satisfying performance obligations, par and $2,855 . $17,728 14,874 The Company elected to apply the practical expedient in accordance with Accounting Standards Codification (ASC) — Revenue Recognition did not evaluate contracts of one year or less for the existence of a significant financing component The Company’s sales revenue is primarily derived from the sale of its oxygen concentrator products to individual consumers, home medical equipment providers, distributors, the Company’s private label partner and resellers worldwide. Sales revenue is classified into two areas: business-to-business sales and direct-to-consumer sales. The following table sets forth the Company’s sales revenue disaggregated by sales channel and geographic region: (amounts in thousands) Years ended December 31, Revenue by region and category 2019 2018 2017 Business-to-business domestic sales $ 106,428 $ 116,581 $ 83,390 Business-to-business international sales 77,960 77,333 55,519 Direct-to-consumer domestic sales 156,158 142,101 86,583 Total sales revenue $ 340,546 $ 336,015 $ 225,492 Rental revenue The Company recognizes equipment rental revenue over the non-cancelable lease term, which is one month, less estimated adjustments, in accordance with ASC 842— Leases The lease term begins on the date products are shipped to patients and are recorded at amounts estimated to be received under reimbursement arrangements with third-party payors, including Medicare, private payors, and Medicaid. Due to the nature of the industry and the reimbursement environment in which the Company operates, certain estimates are required to record net revenue and accounts receivable at their net realizable values. Inherent in these estimates is the risk that they will have to be revised or updated as additional information becomes available. Specifically, the complexity of many third-party billing arrangements and the uncertainty of reimbursement amounts for certain services from certain payors may result in adjustments to amounts originally recorded. Such adjustments are typically identified and recorded at the point of cash application, claim denial or account review. The Company adjusts revenue for historical trends on revenue adjustments due to timely filings, deaths, hospice, and other types of analyzable adjustments on a monthly basis to record rental revenue at the expected collectible amounts. Accounts receivable are reduced by an allowance for doubtful accounts which provides for those accounts from which payment is not expected to be received although product was delivered and revenue was earned. The determination that an account is uncollectable, and the ultimate write-off of that account occurs once collection is considered to be highly unlikely, and it is written-off and charged to the allowance at that time. Amounts billed but not earned due to the timing of the billing cycle are deferred and recognized in revenue on a straight-line basis over the monthly billing period. For example, if the first day of the billing period does not fall on the first of the month, then a portion of the monthly billing period will fall in the subsequent month and the related revenue and cost would be deferred based on the service days in the following month. The lease agreements generally contain lease and non-lease components. Non-lease components primarily include payments for supplies. The Company elected the practical expedient to treat the lease and non-lease components as a single lease component. Rental revenue is recognized as earned, less estimated adjustments. Revenue not billed at the end of the period is reviewed for the likelihood of collections and accrued. The rental revenue stream is not guaranteed, and payment will cease if the patient no longer needs oxygen or returns the equipment. Revenue recognized is at full estimated allowable amounts; transfers to secondary insurances or patient responsibility have no net effect on revenue. Rental revenue is earned for that entire month if the patient is on service on the first day of the 30-day period commencing on the recurring date of service for a particular claim, regardless if there is a change in condition or death after that date. Included in rental revenue are unbilled amounts for which the revenue recognition criteria had been met as of period-end but were not yet billed to the payor. The estimate of net unbilled rental revenue recognized is based on historical trends and estimates of future collectability. In addition, the Company estimates potential future adjustments and write-offs of these unbilled amounts and includes these estimates in the allowance for adjustments and write-offs of rental revenue which is netted against gross receivables. Fair value accounting 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. Fair value of financial instruments 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 December 31, 2019 Gross Cash Adjusted unrealized and cash Marketable (amounts in thousands) 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 As of December 31, 2018 Gross Cash Adjusted unrealized and cash Marketable (amounts in thousands) cost gains (losses) Fair value equivalents securities Cash $ 33,671 $ — $ 33,671 $ 33,671 $ — Level 1: Money market accounts 158,438 — 158,438 158,438 — Level 2: Corporate bonds 13,629 (16 ) 13,613 — 13,613 U.S. Treasury securities 34,620 7 34,627 4,525 30,102 Total $ 240,358 $ (9 ) $ 240,349 $ 196,634 $ 43,715 The following table summarizes the estimated fair value of the Company’s investments in marketable securities, classified by the contractual maturity date of the securities: December 31, (amounts in thousands) 2019 Due within one year $ 11,057 Due in one year through five years — Total $ 11,057 Fair value of 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 within stockholders’ equity and are recognized in the consolidated statements of comprehensive income 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 payable of $514 and a related receivable of $472 as of December 31, 2019 and 2018, 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 related to the hedging relationship. Fair value of accumulated other comprehensive income (loss) The components of accumulated other comprehensive income (loss) were as follows: As of December 31, 2019 Foreign Unrealized Unrealized Accumulated currency gains on gains (losses) other translation marketable on cash comprehensive (amounts in thousands) adjustments securities flow hedges income (loss) Balance as of December 31, 2018 $ 394 $ — $ 330 $ 724 Other comprehensive income (loss) (123 ) 6 (694 ) (811 ) Balance as of December 31, 2019 $ 271 $ 6 $ (364 ) $ (87 ) As of December 31, 2018 Foreign Unrealized Unrealized Accumulated currency gains (losses) on gains (losses) other translation marketable on cash comprehensive (amounts in thousands) adjustments securities flow hedges income Balance as of December 31, 2017 $ 363 $ (17 ) $ (74 ) $ 272 Other comprehensive income 31 17 404 452 Balance as of December 31, 2018 $ 394 $ — $ 330 $ 724 Comprehensive income (loss) is the total net earnings and all other non-owner changes in equity. Except for net income 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). Fair value of earnout liability The earnout liability will be adjusted to fair value at each reporting date until settled. At the end of each reporting period after the acquisition date, the arrangement is remeasured at its fair value, with changes in fair value recorded in earnings. Changes in fair value will be recognized in general and administrative expense. The Company 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 The following table provides quantitative information about Level 3 inputs for fair value measurement of the earnout liability as of the acquisition date and December 31, 2019. Significant increases or decreases in these inputs in isolation could result in a significant impact on our fair value measurement: At acquisition As of Simulation input August 9, 2019 December 31, 2019 Revenue volatility 35.00 % 35.00 % WACC 12.50 % 13.00 % 20-year risk free rate 2.03 % 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: Twelve months ended (amounts in thousands) December 31, 2019 Balance at beginning of period $ — Addition for acquisition 25,749 Change in fair value 810 Balance at end of period $ 26,559 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. Cash, cash equivalents, and marketable securities consist of the following: (amounts in thousands) December 31, Cash and cash equivalents 2019 2018 Cash $ 51,560 $ 33,671 Money market accounts 146,477 158,438 U.S. Treasury securities — 4,525 Total cash and cash equivalents $ 198,037 $ 196,634 Marketable securities Corporate bonds 2,013 13,613 U. S. Treasury securities 9,044 30,102 Total marketable securities $ 11,057 $ 43,715 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 primarily 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. Prior to the adoption of ASC 842, the Company separately recorded an allowance for doubtful accounts by charging bad debt expense, which is now recorded as part of rental revenue adjustments during the year ended December 31, 2019. As of December 31, 2019 and December 31, 2018, included in accounts receivable on the consolidated balance sheets were earned but unbilled receivables of $590 and $589, 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. For the years ended December 31, 2019 and December 31, 2018, the Company had increases of $611 and $1,757, respectively, in the provision for bad debt and revenue adjustments related to prior years. Gross accounts receivable balance concentrations by major category as of December 31, 2019 and December 31, 2018 were as follows: As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Gross accounts receivable $ % $ % Rental (1) $ 3,003 8.3 % $ 3,406 8.7 % Business-to-business and other receivables (2) 33,101 91.7 % 35,656 91.3 % Total gross accounts receivable $ 36,104 100.0 % $ 39,062 100.0 % Net accounts receivable (gross accounts receivable, net of allowances) balance concentrations by major category as of December 31, 2019 and December 31, 2018 were as follows: As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Net accounts receivable $ % $ % Rental (1) $ 2,464 7.2 % $ 2,413 6.5 % Business-to-business and other receivables (2) 31,861 92.8 % 34,628 93.5 % Total net accounts receivable $ 34,325 100.0 % $ 37,041 100.0 % (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 $10,695 and $16,198 as of December 31, 2019 and December 31, 2018, 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 December 31, 2019 and allocated up to $18,000 in coverage as of December 31, 2018 for this customer with a $400 deductible and 10% retention. The following table sets forth the percentage breakdown of the Company’s net accounts receivable (gross accounts receivable net of allowances) by aging category by invoice due date as of December 31, 2019 and December 31, 2018. As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Net accounts receivable by aging category $ % $ % Held and Unbilled $ 294 0.8 % $ 80 0.2 % Aged 0-90 days 33,427 97.4 % 36,245 97.9 % Aged 91-180 days 343 1.0 % 425 1.1 % Aged 181-365 days 261 0.8 % 234 0.6 % Aged over 365 days — 0.0 % 57 0.2 % Total net accounts receivable $ 34,325 100.0 % $ 37,041 100.0 % The following table sets forth the accounts receivable allowances as of December 31, 2019 and December 31, 2018: As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Allowances - accounts receivable $ % $ % Doubtful accounts (1) $ 205 0.6 % $ 693 1.8 % Rental revenue adjustments (1) 411 1.1 % 438 1.1 % Sales returns 1,163 3.2 % 890 2.3 % Total allowances - accounts receivable $ 1,779 4.9 % $ 2,021 5.2 % (1) Prior to the adoption of ASC 842, the Company separately recorded an allowance for doubtful accounts by charging bad debt expense. Upon adoption of ASC 842, such balances are recorded as part of rental revenue adjustments to report rental revenue at an expected collectible amount. 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 on a credit basis. The Company also sells its products direct-to-consumers on a primarily prepayment basis. No single customer represented more than 10% of the Company’s total revenue for the year ended December 31, 2019. One single customer represented more than 10% of the Company’s total revenue for the years ended December 31, 2018 and 2017. Two customers each represented more than 10% of the Company’s net accounts receivable balance with accounts receivable balances of $10,695 and $5,228, respectively, as of December 31, 2019, and $16,198 and $4,155, respectively, as of December 31, 2018. 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 year ended December 31, 2019, the Company’s three major vendors accounted for 23.2%, 13.9% and 9.4%, respectively, of total raw material purchases. For the year ended December 31, 2018, the Company’s three major vendors accounted for 20.0%, 11.9% and 10.2%, respectively, of total raw material purchases. A portion of revenue is earned from sales outside the United States. Approximately 70.2% and 74.8% of the non-U.S. revenue for the years ended December

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2019
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. 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. The 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: (amounts in thousands) 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 twelve months ended December 31, 2019 and the twelve months ended December 31, 2018 presents the revenue and net income assuming the acquisition of New Aera had occurred as of January 1, 2018. Twelve months ended December 31, (amounts in thousands) 2019 2018 Total revenue $ 361,953 $ 358,134 Net income $ 13,256 $ 41,498

Goodwill and Other Identifiable

Goodwill and Other Identifiable Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Other Identifiable Intangible Assets	4. Goodwill and other identifiable intangible assets Goodwill The changes in the carrying amount of goodwill for the years ended December 31, 2019 and 2018 were as follows: (amounts in thousands) Balance as of December 31, 2017 $ 2,363 Translation adjustment (106 ) Balance as of December 31, 2018 $ 2,257 Translation adjustment (45 ) Acquisition 30,742 Balance as of December 31, 2019 $ 32,954 Intangible assets There were no impairments recorded related to the Company’s intangible assets as of December 31, 2019 and 2018. Amortization expense for intangible assets for the years ended December 31, 2019, 2018 and 2017 was $4,160, $1,265 and $507, respectively. The following tables represent the changes in net carrying values of the intangibles as of the respective dates: Average estimated Gross (amounts in thousands) 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 Average estimated Gross (amounts in thousands) useful lives carrying Accumulated December 31, 2018 (in years) amount amortization Net amount Licenses 10 $ 185 $ 155 $ 30 Patents and websites 5 4,164 1,640 2,524 Customer relationships 4 1,373 572 801 Non-compete agreement 2.3 229 154 75 Commercials 2-3 633 308 325 Total $ 6,584 $ 2,829 $ 3,755 Annual estimated amortization expense for each of the succeeding fiscal years is as follows: December 31, (amounts in thousands) 2019 2020 $ 8,970 2021 8,680 2022 8,367 2023 7,792 2024 7,788 Thereafter 35,936 Total $ 77,533

Current Liabilities

Current Liabilities	12 Months Ended
	Dec. 31, 2019
Payables And Accruals [Abstract]
Current Liabilities	5. Current liabilities Accounts payable and accrued expenses as of December 31, 2019 and 2018 consisted of the following: December 31, (amounts in thousands) 2019 2018 Accounts payable $ 16,399 $ 13,720 Accrued inventory (in-transit and unvouchered receipts) and trade payables 11,124 9,597 Accrued purchasing card liability 1,675 2,089 Accrued franchise, sales and use taxes 713 518 Other accrued expenses 819 862 Accounts payable and accrued expenses $ 30,730 $ 26,786 Accrued payroll as of December 31, 2019 and 2018 consisted of the following: December 31, (amounts in thousands) 2019 2018 Accrued bonuses $ 87 $ 4,780 Accrued wages and other payroll related items 3,158 3,494 Accrued vacation 2,169 1,959 Accrued employee stock purchase plan deductions 801 1,174 Accrued payroll $ 6,215 $ 11,407

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	6. Leases The As a result of the MedSupport acquisition, the Company leases a property owned by a related party. Operating lease cost for the property was $31 and $33 for the years ended December 31, 2019 and 2018, respectively, 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: (amounts in thousands) Twelve months ended December 31, 2019 Cash paid for operating lease liabilities $ 2,486 Operating lease cost 2,269 Non-cash right-of-use assets obtained in exchange for new operating lease obligations 7,855 Weighted-average remaining lease term 2.6 years Weighted-average discount rate 3.8 % Maturities of lease liabilities due in the 12-month period ending December 31, 2020 $ 2,228 2021 1,604 2022 1,284 2023 1,217 2024 917 Thereafter — 7,250 Less imputed interest (534 ) Total lease liabilities $ 6,716 Operating lease liability - current $ 2,014 Operating lease liability - noncurrent 4,702 Total lease liabilities $ 6,716 As of December 31, 2019, the Company has additional operating leases for its corporate headquarters in California and commercial and industrial space in Texas that have not yet commenced, with total minimum lease payments of $27,215. 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 commercial and industrial space in Texas will increase annually by two and one-half percent (2.5%) at each annual adjustment date thereafter. These operating leases will commence in 2020 with a lease term of 10-11 years. This table does not include lease payments that were not fixed at commencement or modification. Supplemental information for comparative periods As of December 31, 2018, prior to the adoption of Topic 842, future minimum payments under operating leases having initial or remaining non-cancelable lease terms in excess of one year were as follows: (amounts in thousands) Operating leases (1) 2019 $ 2,450 2020 2,212 2021 1,593 2022 1,273 2023 1,215 Thereafter 917 Total minimum payments $ 9,660 (1) Includes future minimum payments for leases which have not yet commenced.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	7. Income taxes The components of the Company’s income before provision for income taxes are as follows: Years ended December 31, (amounts in thousands) 2019 2018 2017 United States $ 22,553 $ 40,245 $ 29,121 Foreign 1,719 210 535 Income before provision for income taxes $ 24,272 $ 40,455 $ 29,656 The provision for income taxes consists of the following: Years ended December 31, (amounts in thousands) 2019 2018 2017 Current tax expense (benefit) Federal $ (330 ) $ — $ 245 State 136 (40 ) 240 Foreign 560 171 206 Total current tax expense 366 131 691 Deferred tax expense (benefit) Federal 3,497 (9,774 ) 8,709 State (396 ) (1,630 ) 92 Foreign (145 ) (117 ) (71 ) Total deferred tax expense (benefit) 2,956 (11,521 ) 8,730 Tax benefit for change in valuation allowance — — (767 ) Total deferred tax expense (benefit), net 2,956 (11,521 ) 7,963 Income tax expense (benefit) $ 3,322 $ (11,390 ) $ 8,654 The components of deferred tax assets and liabilities consist of the following: (amounts in thousands) As of December 31, Deferred tax assets (liabilities) 2019 2018 Accrued expenses $ 7,981 $ 8,033 Net operating loss and credit carryforward 20,087 19,805 Allowance, reserves and other 1,984 3,490 Stock-based compensation 3,257 3,253 Lease liability 1,627 — Deferred tax assets 34,936 34,581 Property, plant, and equipment (2,961 ) (4,683 ) Intangible amortization (16,192 ) — Right-of-use asset (1,418 ) — Deferred tax liabilities (20,571 ) (4,683 ) Total $ 14,365 $ 29,898 Reconciliation of the federal statutory income tax rate to the effective income tax rate for the years ended December 31, 2019, 2018 and 2017 is as follows: Years ended December 31, 2019 2018 2017 U.S. Statutory rate 21.00 % 21.00 % 34.00 % State income taxes, net of federal benefit 3.70 (3.73 ) 0.37 Stock-based compensation (0.81 ) (45.01 ) (30.40 ) Change in valuation allowance — — (2.59 ) R&D credit, net of reserve (8.97 ) (1.39 ) (1.43 ) Expiration of net operating losses — — 2.76 Effect of U.S tax law change — — 25.55 Other (1.24 ) 0.98 0.92 Effective income tax rate 13.68 % (28.15)% 29.18 % On December 22, 2017, TCJA was enacted into law, which significantly changes existing U.S. tax law and includes numerous provisions that affect the Company’s business. Changes include, but are not limited to, a corporate tax rate decrease from 34% to 21% effective for tax years beginning after December 31, 2017, expensing of capital expenditures, the transition of U.S. international taxation from a worldwide tax system to a territorial system, a one-time transition tax on the mandatory deemed repatriation of cumulative foreign earnings, and limitations on the deductibility of certain executive compensation and other deductions Company is required to recognize the effect of the tax law changes in the period of enactment, including the transition tax, re-measuring the Company’s U.S. deferred tax assets and liabilities, as well as reassessing the net realizability of the Company’s deferred tax assets and liabilities. During the fourth quarter of 2017, the Company recorded a provisional net charge of $ 7,578 related to the TCJA due to the remeasurement of its deferred tax assets . The re was no impact related to the one-time transition tax on the mandatory deemed repatriation of foreign earnings. As of December 31, 2018, the Company completed its evaluation and analysis of the TCJA and there was no additional adjustment to the provisional amount recorded in the fourth quarter of 2017 . 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 2015 for federal and prior to 2014 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. As of December 31, 2019, the Company had $54,883 and $25,679 of federal and state net operating loss carryforwards, respectively, and $46,426 of the total federal net operating loss carryforwards have an indefinite life while the remaining federal and state net operating loss carryforwards begin to expire in 2033 and 2028, respectively, if not utilized. As of December 31, 2019, the Company had federal and California research and development credit carryforward of $4,511 and $4,006, respectively. The federal credit will begin to expire in 2022; the California credit has indefinite carryforward. Utilization of the Company’s net operating loss and tax credit carryforwards may be subject to annual limitations arising from ownership change limitations provided by the Internal Revenue Code and similar state provisions. Such annual limitations could result in the expiration of the net operating loss and tax credit carryforwards before their utilization. The Company assess the available positive and negative evidence to estimate whether sufficient future taxable income will be generated to permit the use of deferred tax assets. As of December 31, 2019, the Company determined that it is more likely than not that deferred tax assets are realizable due to significant positive evidence of cumulative earnings. Accordingly, the Company did not record a valuation allowance as of December 31, 2019. The Company recognizes interest and penalties on taxes, within its income tax provision on its consolidated statements of comprehensive income. No significant interest or penalties were recognized during the periods presented. Included in the balance of unrecognized tax benefits as of December 31, 2019, 2018 and 2017, were $1,889, $1,294 and $1,062, respectively, of tax benefits that, if recognized, would affect the effective tax rate. The Company believes that there will be no significant increases or decreases to unrecognized tax benefits within the next 12 months. A reconciliation of the beginning and ending amount of unrecognized tax benefit is as follows: (amounts in thousands) December 31, Reconciliation of liability for unrecognized tax benefits 2019 2018 2017 Balance at beginning of period $ 1,294 $ 1,062 $ 934 Additions based on tax positions related to current year 595 232 128 Balance at end of period $ 1,889 $ 1,294 $ 1,062

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ equity Common stock Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors, subject to the prior rights of holders of other classes of stock outstanding. Preferred stock Pursuant to the amended and restated certificate of incorporation filed by the Company in connection with the completion of its initial public offering, the Company’s board of directors is authorized to issue up to 10,000,000 shares of preferred stock in one or more series and to fix the rights, preferences, privileges and restrictions thereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, redemption rights, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of common stock. The issuance of preferred stock could adversely affect the voting power of holders of common stock and the likelihood that such holders will receive dividend payments and payments upon liquidation. In addition, the issuance of preferred stock could have the effect of delaying, deferring or preventing change in the Company’s control or other corporate action. As of December 31, 2019 and 2018, no shares of preferred stock were issued or outstanding, and the board of directors has not authorized or designated any rights, preferences, privileges and restrictions for any class of preferred stock. Dividends There were no dividends declared during the years ended December 31, 2019, 2018 and 2017. Stock incentive plans 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 December 31, 2019, 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 December 31, 2019, options to purchase 141,986 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 December 31, 2019, awards with respect to 1,064,545 shares of the Company’s common stock were outstanding, and 1,807,572 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 the year ended December 31, 2019, 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 years ended December 31, 2019, 2018 and 2017 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, 2016 2,355,527 $0.60-$58.95 $ 28.22 5.42 $ 38.95 Granted 64,498 83.30 83.30 Exercised (520,393 ) 0.60-58.95 24.16 Forfeited (63,173 ) 24.52-58.95 43.74 Expired (33 ) 8.70 8.70 Outstanding as of December 31, 2017 1,836,426 0.60-83.30 30.77 4.58 88.31 Vested and exercisable as of December 31, 2017 1,176,504 0.60-83.30 24.33 4.39 94.75 Vested and expected to vest as of December 31, 2017 1,792,871 0.60-83.30 30.50 4.58 88.58 Outstanding as of December 31, 2017 1,836,426 0.60-83.30 30.77 4.58 88.31 Granted — — — Exercised (708,319 ) 0.60-58.95 24.22 Forfeited (771 ) 24.52-44.19 28.24 Expired — — — Outstanding as of December 31, 2018 1,127,336 0.75-83.30 34.89 3.84 89.28 Vested and exercisable as of December 31, 2018 851,039 0.75-83.30 32.12 3.75 92.05 Vested and expected to vest as of December 31, 2018 1,109,280 0.75-83.30 34.75 3.84 89.42 Outstanding as of December 31, 2018 1,127,336 0.75-83.30 34.89 3.84 89.28 Granted — — — Exercised (109,291 ) 0.75-58.95 28.45 Forfeited (37,161 ) 38.54-58.95 44.58 Expired — — — Outstanding as of December 31, 2019 980,884 0.75-83.30 35.24 2.84 34.07 Vested and exercisable as of December 31, 2019 929,825 0.75-83.30 34.73 2.81 34.64 Vested and expected to vest as of December 31, 2019 977,589 $0.75-$83.30 $ 35.21 2.84 $ 34.11 The total intrinsic value of options exercised during the years ended December 31, 2019, 2018, and 2017 was $7,910, $98,743, and $33,931, respectively. The unrecognized compensation expense related to non-vested stock-based compensation granted under the Plans as of December 31, 2019 was $691. 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 years ended December 31, 2019 and December 31, 2018 are 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, 2016 — — — $ — Granted 42,028 13,109 55,137 90.05 Vested — — — — Forfeited/canceled — — — — Unvested restricted stock units as of December 31, 2017 (1) 42,028 13,109 55,137 $ 90.05 Unvested and expected to vest restricted stock units outstanding as of December 31, 2017 48,589 $ 89.95 Unvested restricted stock units as of December 31, 2017 42,028 13,109 55,137 $ 90.05 Granted 31,877 — 31,877 143.50 Vested (13,742 ) (4,370 ) (18,112 ) 89.35 Forfeited/canceled (1,574 ) — (1,574 ) 106.55 Unvested restricted stock units as of December 31, 2018 (1) 58,589 8,739 67,328 $ 115.16 Unvested and expected to vest restricted stock units outstanding as of December 31, 2018 62,504 $ 115.98 Unvested restricted stock units as of December 31, 2018 58,589 8,739 67,328 $ 115.16 Granted 87,902 — 87,902 75.56 Vested (24,680 ) (4,366 ) (29,046 ) 123.53 Forfeited/canceled (12,835 ) (1,239 ) (14,074 ) 102.89 Unvested restricted stock units as of December 31, 2019 (1) 108,976 3,134 112,110 $ 83.48 Unvested and expected to vest restricted stock units outstanding as of December 31, 2019 103,087 $ 83.22 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, 2016 — — — $ — Granted 20,789 20,785 41,574 91.52 Vested — — — — Forfeited/canceled — — — — Unvested restricted stock awards outstanding as of December 31, 2017 (1) 20,789 20,785 41,574 $ 91.52 Unvested and expected to vest restricted stock awards outstanding as of December 31, 2017 34,051 $ 91.52 Unvested restricted stock awards outstanding as of December 31, 2017 20,789 20,785 41,574 $ 91.52 Granted 22,645 33,964 56,609 130.89 Vested (6,497 ) (6,928 ) (13,425 ) 91.52 Forfeited/canceled — — — — Unvested restricted stock awards outstanding as of December 31, 2018 (1) 36,937 47,821 84,758 $ 115.80 Unvested and expected to vest restricted stock awards outstanding as of December 31, 2018 65,773 $ 115.85 Unvested restricted stock awards outstanding as of December 31, 2018 36,937 47,821 84,758 $ 115.80 Granted 54,853 40,166 95,019 86.10 Vested (13,627 ) (15,732 ) (29,359 ) 115.37 Forfeited/canceled (7,093 ) (9,627 ) (16,720 ) 109.11 Unvested restricted stock awards outstanding as of December 31, 2019 (1) 71,070 62,628 133,698 $ 95.74 Unvested and expected to vest restricted stock awards outstanding as of December 31, 2019 79,473 $ 90.31 (1 ) Outstanding restricted stock units and restricted stock awards are based on the maximum payout of the targeted number of shares. As of December 31, 2019, the unrecognized compensation cost related to unvested employee restricted stock units and restricted stock awards was $12,829, excluding estimated forfeitures. This amount is expected to be recognized over a weighted-average period of 2.7 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 December 31, 201 9 , a total of 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 equal to the least of: • 179,069 • 1.5 • such other amount as may be determined by the administrator. For 2019, 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 years ended December 31, 2019, 2018 and 2017, was as follows: (amounts in thousands) Years ended December 31, Stock-based compensation expense by type of award: 2019 2018 2017 Stock option plan awards $ 2,977 $ 6,015 $ 7,652 Restricted stock units and restricted stock awards 5,413 5,890 1,447 Employee stock purchase plan 739 885 541 Total stock-based compensation expense $ 9,129 $ 12,790 $ 9,640 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 years ended December 31, 2019, 2018 and 2017 has been reduced for estimated forfeitures of stock option plan awards at a rate of 7.3%, 7.3% and 7.3%, respectively. The employee stock-based compensation expense recognized for the years ended December 31, 2019, 2018 and 2017 was reduced for estimated forfeitures of restricted stock at a rate of 4.4%, 4.7% and 6.0%, respectively. ASC 718 – Compensation-Stock Compensation For the years ended December 31, 2019, 2018 and 2017, 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: Years ended December 31, (amounts in thousands) 2019 2018 2017 Cost of revenue $ 890 $ 1,060 $ 845 Research and development 1,100 1,314 1,015 Sales and marketing 1,755 2,355 1,558 General and administrative 5,384 8,061 6,222 Total stock-based compensation expense $ 9,129 $ 12,790 $ 9,640 Valuation assumptions The employee stock-based compensation expense is recognized under ASC 718. Stock-based compensation cost for stock awards is based on the number of shares ultimately expected to vest, estimated at each reporting date based on management’s expectations regarding the relevant performance criteria. The value of the award that is ultimately expected to vest is recognized as expense on a straight-line basis over the employee’s requisite service period for stock awards with a time-based service condition and on a graded vesting basis over the employee’s requisite service period for stock awards with performance and time-based service conditions. Stock-based compensation cost for stock options and employee stock purchase plan are determined at the grant date using the Black-Scholes option pricing model. The following table displays the assumptions that have been applied to estimate the fair value of stock option awards on the date of grant using the Black-Scholes option pricing model. During 2019 and 2018, the Company did not grant any stock option awards. 2017 Expected term (years) 3.54-4.00 Risk free interest rate 1.65-1.73% Expected dividend yield None Volatility 41.61-42.15% Under these assumptions, the total weighted-average fair value of stock options granted during the year ended December 31, 2017 was $8,929. The following table displays the assumptions that have been applied to estimate the fair value of the Company’s shares to be issued under the ESPP using the Black-Scholes option pricing model. 2019 2018 2017 Expected term (years) 0.50 0.50 0.50 Risk free interest rate 1.75-2.53% 1.63-2.46% 1.15-1.63% Expected dividend yield None None None Volatility 44.00-47.00% 37.34-44.00% 42.35-45.34% 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 $871, $865, and $557, net of forfeitures, to the 401(k) plan for the years ended December 31, 2019, 2018 and 2017, respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. Commitments and contingencies Non-cancelable contractual obligations The Company enters into non-cancelable contractual obligations for software licenses and maintenance agreements. At December 31, 2019, the minimum aggregate payments due under specified non-cancelable contractual obligations Non-cancelable contractual (amounts in thousands) obligations 2020 $ 578 2021 457 2022 — 2023 — 2024 — Thereafter — Total $ 1,035 Purchase obligations The Company had approximately $54,500 of outstanding purchase orders with its outside vendors and suppliers as of December 31, 2019. Warranty obligation The following table identifies the changes in the Company’s aggregate product warranty liabilities for the twelve-month periods ended December 31, 2019, 2018 and 2017, respectively: December 31, (amounts in thousands) 2019 2018 2017 Product warranty liability at beginning of period $ 9,530 $ 6,171 $ 3,480 Accruals for warranties issued 8,131 7,693 5,275 Adjustments related to preexisting warranties (including changes in estimates) 1,433 90 200 Settlements made (in cash or in kind) (6,523 ) (4,424 ) (2,784 ) Product warranty liability at end of period $ 12,571 $ 9,530 $ 6,171 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) ensures health insurance portability, reduces healthcare fraud and abuse, guarantees security and privacy of health information, and enforces standards for health information. The Health Information Technology for Economic and Clinical Health Act (HITECH Act) 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. Breathe alleged willful infringement on certain patents, declared that inventorship was incorrectly assigned and their 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 inventorship of patents to be corrected, 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. The Company intends to vigorously defend itself against these allegations. 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	12 Months Ended
	Dec. 31, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Foreign currency exchange contracts and hedging	10. Foreign currency exchange contracts and hedging As of December 31, 2019 and December 31, 2018, the Company’s total non-designated and designated derivative contracts had notional amounts totaling approximately $3,396 and $35,708, respectively, and $2,336 and $21,374, respectively. These contracts were comprised of offsetting contracts with the same counterparty, each expires within one to twelve months. During the years ended December 31, 2019, 2018, and 2017, these contracts had, net of tax, an unrealized loss of $694, an unrealized gain of $404, and an unrealized loss of $121, 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 years ended December 31, 2019, 2018 and 2017, there were no ineffective portions relating to these hedges and the hedges remained effective through their respective settlement dates. As of December 31, 2019, the Company had eleven designated hedges and one non-designated hedges. As of December 31, 2018, the Company had twenty-nine designated hedges and four non-designated hedges.

Quarterly Summary of Informatio

Quarterly Summary of Information (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly summary of information (unaudited)	11. Quarterly summary of information (unaudited) The following table sets forth the Company’s unaudited quarterly statements of income data in dollars for each of the eight quarters in the period ended December 31, 2019. The Company has prepared the quarterly statements of income data on a basis consistent with the audited financial statements. In the opinion of management, the financial information reflects all adjustments, consisting only of normal recurring adjustments, which the Company considers necessary for a fair presentation of this data. The results of historical periods are not necessarily indicative of the results of operations for any future period. (amounts in thousands, except share and per share amounts) Quarterly Results 2019 Q1 March Q2 June Q3 September Q4 December Total revenue $ 90,202 $ 101,063 $ 91,761 $ 78,917 Gross profit 44,409 50,215 43,315 33,922 Income (loss) before provision (benefit) for income taxes 6,072 13,684 8,753 (4,237 ) Provision (benefit) for income taxes 770 3,524 1,890 (2,862 ) Net income (loss) 5,302 10,160 6,863 (1,375 ) Net income (loss) per share attributable to common stockholders: Basic $ 0.24 $ 0.47 $ 0.31 $ (0.06 ) Diluted (1) $ 0.24 $ 0.45 $ 0.31 $ (0.06 ) Weighted-average number of shares used in calculating net income (loss) per share attributable to common stockholders: Basic common shares 21,750,305 21,815,634 21,840,473 21,878,004 Diluted common shares 22,534,885 22,359,679 22,191,688 21,878,004 (1) Due to net loss for period Q4 December, dilutive loss per share is the same as basic. (amounts in thousands, except share and per share amounts) Quarterly Results 2018 Q1 March Q2 June Q3 September Q4 December Total revenue $ 79,051 $ 97,238 $ 95,291 $ 86,531 Gross profit 37,727 48,470 48,813 43,570 Income before benefit for income taxes 9,687 13,646 11,299 5,823 Benefit for income taxes (1,071 ) (964 ) (5,133 ) (4,222 ) Net income 10,758 14,610 16,432 10,045 Net income per share attributable to common stockholders: Basic $ 0.51 $ 0.69 $ 0.77 $ 0.47 Diluted $ 0.48 $ 0.65 $ 0.73 $ 0.44 Weighted-average number of shares used in calculating net income per share attributable to common stockholders: Basic common shares 21,026,154 21,172,170 21,324,256 21,544,202 Diluted common shares 22,295,213 22,503,749 22,659,052 22,600,038 Earnings per share is computed independently for each of the quarters presented. Therefore, the sum of the quarterly amounts will not necessarily equal the total for the year.

Schedule II_ Valuation and Qual

Schedule II: Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2019
Valuation And Qualifying Accounts [Abstract]
Schedule II: Valuation and Qualifying Accounts	Schedule II: Valuation and Qualifying Accounts Balance at Beginning Balance at (amounts in thousands) of Year Additions Deletions Adjustments End of Year Year ended December 31, 2019 Allowance for doubtful accounts (1) $ 693 $ 612 $ 1,100 $ — $ 205 Allowance for sales returns (2) 890 17,036 16,763 — 1,163 Allowance for rental revenue adjustments (3) 438 1,762 1,789 — 411 Allowance for rental asset loss (4) 594 188 387 — 395 Year ended December 31, 2018 Allowance for doubtful accounts (1) $ 1,415 $ 1,685 $ 2,677 $ 270 $ 693 Allowance for sales returns (2) 904 15,834 15,848 — 890 Allowance for rental revenue adjustments (3) 947 2,678 2,917 (270 ) 438 Allowance for rental asset loss (4) 754 408 568 — 594 Year ended December 31, 2017 Allowance for doubtful accounts (1) $ 1,869 $ 3,864 $ 4,418 $ 100 $ 1,415 Allowance for sales returns (2) 585 9,909 9,590 — 904 Allowance for rental revenue adjustments (3) 6,078 5,057 10,088 (100 ) 947 Allowance for rental asset loss (4) 725 561 532 — 754 (1) The additions to the allowance for doubtful accounts represent the estimates of bad debt expense based upon factors for which the company evaluates the collectability of accounts receivable, with actual recoveries netted into additions. Deductions are the actual write-offs of the receivables. (2) The additions to the allowance for sales returns represent estimates of returns based upon historical returns experience, primarily for the direct-to-consumer sales channel. Deductions are the actual returns of products. (3) The additions to the allowance for rental revenue adjustments represent estimates of revenue adjustments that will need to be recorded for billing adjustments on rental revenue, net of recoveries. Deductions are the actual adjustments and write-offs of the rental receivables for such revenue adjustments. ( 4 ) The additions to the allowance for rental asset loss represent estimated losses of the Company’s rental assets that will potentially be unrecoverable from the patient. Deductions are the actual write-offs of the rental assets.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of presentation 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).
Basis of Consolidation	Basis of consolidation The consolidated financial statements include the accounts of Inogen, Inc. and its wholly owned subsidiary. All intercompany balances and transactions have been eliminated.
Accounting Estimates	Accounting 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.
Revenue	Revenue The Company generates revenue primarily from sales and rentals of its products. The Company’s products consist of its proprietary line of oxygen concentrators, non-invasive ventilators, and related accessories. Other revenue, which is included in sales revenue on the Statements of Comprehensive Income, primarily comes from service contracts, replacement parts and freight revenue for product shipments. Sales revenue Revenue is recognized upon transfer of control of promised products or services to customers in an amount that reflects the consideration the Company expects to receive in exchange for those products or services. Revenue from product sales is generally recognized upon shipment of the product but is deferred for certain transactions when control has not yet transferred to the customer. The Company’s product is generally sold with a right of return and the Company may provide other incentives, which are accounted for as variable consideration when estimating the amount of revenue to recognize. Returns and incentives are estimated at the time sales revenue is recognized. The provision for estimated returns is calculated based on historical data and future expectations. Sales revenue incentives within the Company’s contracts are estimated based on the most likely amounts expected on the related sales transactions and recorded as a reduction to revenue at the time of sale in accordance with the terms of the contract. The Company also offers a lifetime warranty for direct-to-consumer sales of its oxygen concentrators. For a fixed price, the Company agrees to provide a fully functional oxygen concentrator for the remaining life of the patient. Lifetime warranties are only offered to patients upon the initial sale of oxygen concentrators directly from the Company and are non-transferable. Lifetime warranties are considered to be a distinct performance obligation that are accounted for separately from its sale of oxygen concentrators with a standard warranty of three years . The revenue is allocated to the distinct lifetime warranty performance obligation based on a relative SSP method. The Company has vendor-specific objective evidence of the selling price for its equipment. To determine the selling price of the lifetime warranty, the Company uses its best estimate of the SSP for the distinct performance obligation as the lifetime warranty is neither separately priced nor is the selling price available through third-party evidence. To calculate the selling price associated with the lifetime warranties, management considers the profit margins of service revenue, the average estimated cost of lifetime warranties and the price of extended warranties. Revenue from the distinct lifetime warranty is deferred after the delivery of the equipment and recognized based on an estimated mortality rate over five years, which is the estimated performance period of the contract based on the average patient life expectancy. Revenue from the sale of the Company’s repair services is recognized when the performance obligations are satisfied and collection of the receivables is probable. Other revenue from the sale of replacement parts is generally recognized when product is shipped to customers. Freight revenue consists of fees associated with the deployment of products internationally and domestically when expedited freight options are requested or when minimum order quantities are not met. Freight revenue is generally recognized upon shipment of the product but is deferred if control has not yet transferred to the customer. Shipping and handling costs for sold products and rental assets shipped to the Company’s customers are included on the consolidated statements of comprehensive income as part of cost of sales revenue and cost of rental revenue, respectively. The payment terms and conditions of customer contracts vary by customer type and the products and services offered. For certain products or services and customer types, the Company requires payment before the products or services are delivered to the customer. The timing of sales revenue recognition, billing and cash collection results in billed accounts receivable and deferred revenue in the consolidated balance sheet. Contract liabilities primarily consist of deferred revenue related to lifetime warranties on direct-to-consumer sales revenue when cash 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 years ended December 31, 2019 and December 31, 2018 was primarily driven by $8,757 and $6,909, respectively, of payments received in advance of satisfying performance obligations, par and $2,855 . $17,728 14,874 The Company elected to apply the practical expedient in accordance with Accounting Standards Codification (ASC) — Revenue Recognition did not evaluate contracts of one year or less for the existence of a significant financing component The Company’s sales revenue is primarily derived from the sale of its oxygen concentrator products to individual consumers, home medical equipment providers, distributors, the Company’s private label partner and resellers worldwide. Sales revenue is classified into two areas: business-to-business sales and direct-to-consumer sales. The following table sets forth the Company’s sales revenue disaggregated by sales channel and geographic region: (amounts in thousands) Years ended December 31, Revenue by region and category 2019 2018 2017 Business-to-business domestic sales $ 106,428 $ 116,581 $ 83,390 Business-to-business international sales 77,960 77,333 55,519 Direct-to-consumer domestic sales 156,158 142,101 86,583 Total sales revenue $ 340,546 $ 336,015 $ 225,492 Rental revenue The Company recognizes equipment rental revenue over the non-cancelable lease term, which is one month, less estimated adjustments, in accordance with ASC 842— Leases The lease term begins on the date products are shipped to patients and are recorded at amounts estimated to be received under reimbursement arrangements with third-party payors, including Medicare, private payors, and Medicaid. Due to the nature of the industry and the reimbursement environment in which the Company operates, certain estimates are required to record net revenue and accounts receivable at their net realizable values. Inherent in these estimates is the risk that they will have to be revised or updated as additional information becomes available. Specifically, the complexity of many third-party billing arrangements and the uncertainty of reimbursement amounts for certain services from certain payors may result in adjustments to amounts originally recorded. Such adjustments are typically identified and recorded at the point of cash application, claim denial or account review. The Company adjusts revenue for historical trends on revenue adjustments due to timely filings, deaths, hospice, and other types of analyzable adjustments on a monthly basis to record rental revenue at the expected collectible amounts. Accounts receivable are reduced by an allowance for doubtful accounts which provides for those accounts from which payment is not expected to be received although product was delivered and revenue was earned. The determination that an account is uncollectable, and the ultimate write-off of that account occurs once collection is considered to be highly unlikely, and it is written-off and charged to the allowance at that time. Amounts billed but not earned due to the timing of the billing cycle are deferred and recognized in revenue on a straight-line basis over the monthly billing period. For example, if the first day of the billing period does not fall on the first of the month, then a portion of the monthly billing period will fall in the subsequent month and the related revenue and cost would be deferred based on the service days in the following month. The lease agreements generally contain lease and non-lease components. Non-lease components primarily include payments for supplies. The Company elected the practical expedient to treat the lease and non-lease components as a single lease component. Rental revenue is recognized as earned, less estimated adjustments. Revenue not billed at the end of the period is reviewed for the likelihood of collections and accrued. The rental revenue stream is not guaranteed, and payment will cease if the patient no longer needs oxygen or returns the equipment. Revenue recognized is at full estimated allowable amounts; transfers to secondary insurances or patient responsibility have no net effect on revenue. Rental revenue is earned for that entire month if the patient is on service on the first day of the 30-day period commencing on the recurring date of service for a particular claim, regardless if there is a change in condition or death after that date. Included in rental revenue are unbilled amounts for which the revenue recognition criteria had been met as of period-end but were not yet billed to the payor. The estimate of net unbilled rental revenue recognized is based on historical trends and estimates of future collectability. In addition, the Company estimates potential future adjustments and write-offs of these unbilled amounts and includes these estimates in the allowance for adjustments and write-offs of rental revenue which is netted against gross receivables.
Fair Value Accounting	Fair value accounting 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. Fair value of financial instruments 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 December 31, 2019 Gross Cash Adjusted unrealized and cash Marketable (amounts in thousands) 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 As of December 31, 2018 Gross Cash Adjusted unrealized and cash Marketable (amounts in thousands) cost gains (losses) Fair value equivalents securities Cash $ 33,671 $ — $ 33,671 $ 33,671 $ — Level 1: Money market accounts 158,438 — 158,438 158,438 — Level 2: Corporate bonds 13,629 (16 ) 13,613 — 13,613 U.S. Treasury securities 34,620 7 34,627 4,525 30,102 Total $ 240,358 $ (9 ) $ 240,349 $ 196,634 $ 43,715 The following table summarizes the estimated fair value of the Company’s investments in marketable securities, classified by the contractual maturity date of the securities: December 31, (amounts in thousands) 2019 Due within one year $ 11,057 Due in one year through five years — Total $ 11,057
Fair Value of Derivative Instruments and Hedging Activities	Fair value of 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 within stockholders’ equity and are recognized in the consolidated statements of comprehensive income 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 payable of $514 and a related receivable of $472 as of December 31, 2019 and 2018, 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 related to the hedging relationship.
Fair Value of Accumulated Other Comprehensive Income (Loss)	Fair value of accumulated other comprehensive income (loss) The components of accumulated other comprehensive income (loss) were as follows: As of December 31, 2019 Foreign Unrealized Unrealized Accumulated currency gains on gains (losses) other translation marketable on cash comprehensive (amounts in thousands) adjustments securities flow hedges income (loss) Balance as of December 31, 2018 $ 394 $ — $ 330 $ 724 Other comprehensive income (loss) (123 ) 6 (694 ) (811 ) Balance as of December 31, 2019 $ 271 $ 6 $ (364 ) $ (87 ) As of December 31, 2018 Foreign Unrealized Unrealized Accumulated currency gains (losses) on gains (losses) other translation marketable on cash comprehensive (amounts in thousands) adjustments securities flow hedges income Balance as of December 31, 2017 $ 363 $ (17 ) $ (74 ) $ 272 Other comprehensive income 31 17 404 452 Balance as of December 31, 2018 $ 394 $ — $ 330 $ 724 Comprehensive income (loss) is the total net earnings and all other non-owner changes in equity. Except for net income 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).
Fair Value of Earnout Liability	Fair value of earnout liability The earnout liability will be adjusted to fair value at each reporting date until settled. At the end of each reporting period after the acquisition date, the arrangement is remeasured at its fair value, with changes in fair value recorded in earnings. Changes in fair value will be recognized in general and administrative expense. The Company 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 The following table provides quantitative information about Level 3 inputs for fair value measurement of the earnout liability as of the acquisition date and December 31, 2019. Significant increases or decreases in these inputs in isolation could result in a significant impact on our fair value measurement: At acquisition As of Simulation input August 9, 2019 December 31, 2019 Revenue volatility 35.00 % 35.00 % WACC 12.50 % 13.00 % 20-year risk free rate 2.03 % 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: Twelve months ended (amounts in thousands) December 31, 2019 Balance at beginning of period $ — Addition for acquisition 25,749 Change in fair value 810 Balance at end of period $ 26,559
Cash, Cash Equivalents, and Marketable Securities	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. Cash, cash equivalents, and marketable securities consist of the following: (amounts in thousands) December 31, Cash and cash equivalents 2019 2018 Cash $ 51,560 $ 33,671 Money market accounts 146,477 158,438 U.S. Treasury securities — 4,525 Total cash and cash equivalents $ 198,037 $ 196,634 Marketable securities Corporate bonds 2,013 13,613 U. S. Treasury securities 9,044 30,102 Total marketable securities $ 11,057 $ 43,715
Accounts Receivable and Allowance for Bad Debts, Returns, and Adjustments	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 primarily 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. Prior to the adoption of ASC 842, the Company separately recorded an allowance for doubtful accounts by charging bad debt expense, which is now recorded as part of rental revenue adjustments during the year ended December 31, 2019. As of December 31, 2019 and December 31, 2018, included in accounts receivable on the consolidated balance sheets were earned but unbilled receivables of $590 and $589, 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. For the years ended December 31, 2019 and December 31, 2018, the Company had increases of $611 and $1,757, respectively, in the provision for bad debt and revenue adjustments related to prior years. Gross accounts receivable balance concentrations by major category as of December 31, 2019 and December 31, 2018 were as follows: As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Gross accounts receivable $ % $ % Rental (1) $ 3,003 8.3 % $ 3,406 8.7 % Business-to-business and other receivables (2) 33,101 91.7 % 35,656 91.3 % Total gross accounts receivable $ 36,104 100.0 % $ 39,062 100.0 % Net accounts receivable (gross accounts receivable, net of allowances) balance concentrations by major category as of December 31, 2019 and December 31, 2018 were as follows: As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Net accounts receivable $ % $ % Rental (1) $ 2,464 7.2 % $ 2,413 6.5 % Business-to-business and other receivables (2) 31,861 92.8 % 34,628 93.5 % Total net accounts receivable $ 34,325 100.0 % $ 37,041 100.0 % (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 $10,695 and $16,198 as of December 31, 2019 and December 31, 2018, 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 December 31, 2019 and allocated up to $18,000 in coverage as of December 31, 2018 for this customer with a $400 deductible and 10% retention. The following table sets forth the percentage breakdown of the Company’s net accounts receivable (gross accounts receivable net of allowances) by aging category by invoice due date as of December 31, 2019 and December 31, 2018. As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Net accounts receivable by aging category $ % $ % Held and Unbilled $ 294 0.8 % $ 80 0.2 % Aged 0-90 days 33,427 97.4 % 36,245 97.9 % Aged 91-180 days 343 1.0 % 425 1.1 % Aged 181-365 days 261 0.8 % 234 0.6 % Aged over 365 days — 0.0 % 57 0.2 % Total net accounts receivable $ 34,325 100.0 % $ 37,041 100.0 % The following table sets forth the accounts receivable allowances as of December 31, 2019 and December 31, 2018: As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Allowances - accounts receivable $ % $ % Doubtful accounts (1) $ 205 0.6 % $ 693 1.8 % Rental revenue adjustments (1) 411 1.1 % 438 1.1 % Sales returns 1,163 3.2 % 890 2.3 % Total allowances - accounts receivable $ 1,779 4.9 % $ 2,021 5.2 % (1) Prior to the adoption of ASC 842, the Company separately recorded an allowance for doubtful accounts by charging bad debt expense. Upon adoption of ASC 842, such balances are recorded as part of rental revenue adjustments to report rental revenue at an expected collectible amount.
Concentration of Credit Risk	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	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 on a credit basis. The Company also sells its products direct-to-consumers on a primarily prepayment basis. No single customer represented more than 10% of the Company’s total revenue for the year ended December 31, 2019. One single customer represented more than 10% of the Company’s total revenue for the years ended December 31, 2018 and 2017. Two customers each represented more than 10% of the Company’s net accounts receivable balance with accounts receivable balances of $10,695 and $5,228, respectively, as of December 31, 2019, and $16,198 and $4,155, respectively, as of December 31, 2018. 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 year ended December 31, 2019, the Company’s three major vendors accounted for 23.2%, 13.9% and 9.4%, respectively, of total raw material purchases. For the year ended December 31, 2018, the Company’s three major vendors accounted for 20.0%, 11.9% and 10.2%, respectively, of total raw material purchases. A portion of revenue is earned from sales outside the United States. Approximately 70.2% and 74.8% of the non-U.S. revenue for the years ended December 31, 2019 and 2018, respectively, were invoiced in Euros. A breakdown of the Company’s revenue from U.S. and non-U.S. sources for the years ended December 31, 2019, 2018 and 2017, respectively, is as follows: Years ended December 31, (amounts in thousands) 2019 2018 2017 U.S. revenue $ 283,983 $ 280,778 $ 193,919 Non-U.S. revenue 77,960 77,333 55,519 Total revenue $ 361,943 $ 358,111 $ 249,438
Inventories	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 $1,076 and $1,085 as of December 31, 2019 and 2018, 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. December 31, (amounts in thousands) 2019 2018 Raw materials and work-in-progress $ 31,676 $ 24,980 Finished goods 5,174 2,756 Less: reserves (1,186 ) (665 ) Inventories, net $ 35,664 $ 27,071
Property and Equipment	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 $2,854, $2,289 and $2,385 for the years ended December 31, 2019, 2018 and 2017, 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 years ended December 31, 2019, 2018 and 2017, respectively. Years ended December 31, (amounts in thousands) 2019 2018 2017 Rental equipment $ 6,253 $ 7,567 $ 9,835 Other property and equipment 3,421 2,463 1,960 Total depreciation and amortization $ 9,674 $ 10,030 $ 11,795 Property and equipment and rental equipment with associated accumulated depreciation is summarized below as of December 31, 2019 and 2018, respectively. (amounts in thousands) December 31, Property and equipment 2019 2018 Rental equipment, net of allowances of $395 and $594, respectively $ 39,308 $ 43,038 Other property and equipment 24,986 21,596 Property and equipment 64,294 64,634 Accumulated depreciation Rental equipment 30,984 31,813 Other property and equipment 13,872 10,480 Accumulated depreciation 44,856 42,293 Property and equipment, net Rental equipment, net of allowances of $395 and $594, respectively 8,324 11,225 Other property and equipment 11,114 11,116 Property and equipment, net $ 19,438 $ 22,341
Long-lived Assets	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 and Intangible Assets	Goodwill and intangible assets Goodwill is tested for impairment on an annual basis as of October 1. Interim testing of goodwill for impairment is also required whenever an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit or asset below its carrying amount. No impairments were recorded as of December 31, 2019 and 2018. Finite-lived intangible assets are amortized over their useful lives and are tested for recoverability whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. Technology, customer relationships and non-compete agreements are amortized using the straight-line method.
Business Combinations	Business combinations The results of operations of the businesses acquired by the Company are included as of the acquisition date. The purchase price of an acquisition is allocated to the underlying assets acquired and liabilities assumed based upon their estimated fair values at the date of acquisition. To the extent the purchase price exceeds the fair value of the net identifiable tangible and intangible assets acquired and liabilities assumed, such excess is allocated to goodwill. The Company may adjust the preliminary purchase price allocation, as necessary, for up to one year after the acquisition closing date if it obtains more information regarding asset valuations and liabilities assumed. Acquisition-related expenses are recognized separately from the business combination and are expensed as incurred.
Leases	Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use (ROU) assets, operating lease liability – current, and operating lease liability – noncurrent on the consolidated balance sheets. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. The Company uses an incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments as the rate implicit in each lease is generally not readily determinable. The operating lease ROU asset also includes any lease payments made to the lessor at or before the commencement date and excludes lease incentives. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has lease agreements with lease and non-lease components. The Company elected the practical expedient to treat the lease and non-lease components as a single lease component. Additionally, the Company elected the practical expedient to not record leases with an initial term of twelve months or less on the consolidated balance sheets.
Loss Contingencies	Loss contingencies The Company is involved in various lawsuits, claims, investigations, and proceedings that arise in the ordinary course of business. The Company records a liability when it believes that it is both probable that a loss has been incurred and the amount can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. The Company reviews at least quarterly and adjusts accordingly to reflect the impact of negotiations, settlements, rulings, advice of legal counsel, and updated information. At this time, the Company has no accrual related to lawsuits, claims, investigations and proceedings.
Research and Development	Research and development Research and development costs are expensed as incurred.
Advertising Costs	Advertising costs Advertising costs, which approximated $40,251, $30,755 and $12,511 during the years ended December 31, 2019, 2018 and 2017, respectively, are expensed as incurred, excluding the production costs of direct response advertising. Advertising costs are included in sales and marketing expense in the accompanying consolidated statements of comprehensive income.
Income Taxes	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 .
Accounting for Stock-Based Compensation	Accounting for stock-based compensation The Company accounts for its stock-based compensation in accordance with ASC 718 — Compensation—Stock Compensation As part of the provisions of ASC 718, the Company is required to estimate potential forfeitures of stock grants and adjust compensation cost recorded accordingly. The estimate of forfeitures will be adjusted over the requisite service period to the extent that actual forfeitures differ, or are expected to differ, from such estimates. Changes in estimated forfeitures will be recognized through a cumulative catch-up adjustment in the period of change and will also impact the amount of stock compensation expense to be recognized in future periods.
Foreign Currency	Foreign currency The functional currency of the Company’s international subsidiary is the local currency. The financial statements of the subsidiary are translated to U.S. dollars using month-end exchange rates for assets and liabilities and average exchange rates for revenue, cost of revenue, operating expense and provision for income taxes. Translation gains and losses are recorded in accumulated other comprehensive income (loss) as a component of stockholders’ equity. Foreign exchange transaction gains and losses resulting from the conversion of the transaction currency to functional currency are reflected as a component of foreign currency exchange gains or losses in other income (expense) in the consolidated statements of comprehensive income.
Earnings Per Share	Earnings per share Earnings per share (EPS) is computed in accordance with ASC 260 — Earnings per Share Basic earnings per share is calculated using the Company’s weighted-average outstanding common shares. Diluted earnings 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: Years ended December 31, (amounts in thousands, except share and per share amounts) 2019 2018 2017 Numerator—basic and diluted: Net income $ 20,950 $ 51,845 $ 21,002 Denominator: Weighted-average common shares - basic common stock (1) 21,821,104 21,266,696 20,683,807 Weighted-average common shares - diluted common stock 22,241,064 22,514,513 21,897,988 Net income per share - basic common stock $ 0.96 $ 2.44 $ 1.02 Net income per share - diluted common stock $ 0.94 $ 2.30 $ 0.96 Denominator calculation from basic to diluted: Weighted-average common shares - basic common stock (1) 21,821,104 21,266,696 20,683,807 Stock options and other dilutive awards 419,960 1,247,817 1,214,181 Weighted-average common shares - diluted common stock 22,241,064 22,514,513 21,897,988 Shares excluded from diluted weighted-average shares: Stock options 53,888 — 37,249 Restricted stock units and restricted stock awards 169,305 39,330 26,064 Shares excluded from diluted weighted-average shares 223,193 39,330 63,313 (1) Unvested restricted stock units and restricted stock awards are not included as shares outstanding in the calculation of basic earnings per share. Vested restricted stock units and restricted stock awards are included in basic earnings 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 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. The computations of diluted net income attributable to common stockholders excluded common stock options, restricted stock units, and restricted stock awards, which were anti-dilutive for the years ended December 31, 2019, 2018 and 2017.
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.
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently issued accounting pronouncements not yet adopted In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (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 . The new guidance modifies the disclosure requirements on fair value measurements. The ASU is effective for fiscal years beginning after December 15, 2019, with early adoption permitted. While the Company continues to evaluate the effect of adopting this guidance, the Company expects the fair value disclosures related to financial instruments, derivative instruments and hedging activities and earnout liabilities will be subject to the new standard. In December 2019, the FASB issued 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 February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) . In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging In January 2018, the FASB issued ASU No. 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting
Prior Period Reclassifications	Prior period reclassifications Certain amounts in prior periods have been reclassified to conform with current period presentation.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Sales Revenue Disaggregated by Sales Channel and Geographic Region	The following table sets forth the Company’s sales revenue disaggregated by sales channel and geographic region: (amounts in thousands) Years ended December 31, Revenue by region and category 2019 2018 2017 Business-to-business domestic sales $ 106,428 $ 116,581 $ 83,390 Business-to-business international sales 77,960 77,333 55,519 Direct-to-consumer domestic sales 156,158 142,101 86,583 Total sales revenue $ 340,546 $ 336,015 $ 225,492
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 December 31, 2019 Gross Cash Adjusted unrealized and cash Marketable (amounts in thousands) 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 As of December 31, 2018 Gross Cash Adjusted unrealized and cash Marketable (amounts in thousands) cost gains (losses) Fair value equivalents securities Cash $ 33,671 $ — $ 33,671 $ 33,671 $ — Level 1: Money market accounts 158,438 — 158,438 158,438 — Level 2: Corporate bonds 13,629 (16 ) 13,613 — 13,613 U.S. Treasury securities 34,620 7 34,627 4,525 30,102 Total $ 240,358 $ (9 ) $ 240,349 $ 196,634 $ 43,715
Summary of Estimated Fair Value of Company's Investments in Marketable Securities Classified by Contractual Maturity Date	The following table summarizes the estimated fair value of the Company’s investments in marketable securities, classified by the contractual maturity date of the securities: December 31, (amounts in thousands) 2019 Due within one year $ 11,057 Due in one year through five years — Total $ 11,057
Summary of Components of Accumulated Other Comprehensive Income (Loss)	The components of accumulated other comprehensive income (loss) were as follows: As of December 31, 2019 Foreign Unrealized Unrealized Accumulated currency gains on gains (losses) other translation marketable on cash comprehensive (amounts in thousands) adjustments securities flow hedges income (loss) Balance as of December 31, 2018 $ 394 $ — $ 330 $ 724 Other comprehensive income (loss) (123 ) 6 (694 ) (811 ) Balance as of December 31, 2019 $ 271 $ 6 $ (364 ) $ (87 ) As of December 31, 2018 Foreign Unrealized Unrealized Accumulated currency gains (losses) on gains (losses) other translation marketable on cash comprehensive (amounts in thousands) adjustments securities flow hedges income Balance as of December 31, 2017 $ 363 $ (17 ) $ (74 ) $ 272 Other comprehensive income 31 17 404 452 Balance as of December 31, 2018 $ 394 $ — $ 330 $ 724
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 the acquisition date and December 31, 2019. Significant increases or decreases in these inputs in isolation could result in a significant impact on our fair value measurement: At acquisition As of Simulation input August 9, 2019 December 31, 2019 Revenue volatility 35.00 % 35.00 % WACC 12.50 % 13.00 % 20-year risk free rate 2.03 % 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: Twelve months ended (amounts in thousands) December 31, 2019 Balance at beginning of period $ — Addition for acquisition 25,749 Change in fair value 810 Balance at end of period $ 26,559
Summary of Cash, Cash Equivalents and Short-term Investments	. Cash, cash equivalents, and marketable securities consist of the following: (amounts in thousands) December 31, Cash and cash equivalents 2019 2018 Cash $ 51,560 $ 33,671 Money market accounts 146,477 158,438 U.S. Treasury securities — 4,525 Total cash and cash equivalents $ 198,037 $ 196,634 Marketable securities Corporate bonds 2,013 13,613 U. S. Treasury securities 9,044 30,102 Total marketable securities $ 11,057 $ 43,715
Schedule of Gross Accounts Receivable Balance Concentrations by Major Category	Gross accounts receivable balance concentrations by major category as of December 31, 2019 and December 31, 2018 were as follows: As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Gross accounts receivable $ % $ % Rental (1) $ 3,003 8.3 % $ 3,406 8.7 % Business-to-business and other receivables (2) 33,101 91.7 % 35,656 91.3 % Total gross accounts receivable $ 36,104 100.0 % $ 39,062 100.0 %
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 December 31, 2019 and December 31, 2018 were as follows: As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Net accounts receivable $ % $ % Rental (1) $ 2,464 7.2 % $ 2,413 6.5 % Business-to-business and other receivables (2) 31,861 92.8 % 34,628 93.5 % Total net accounts receivable $ 34,325 100.0 % $ 37,041 100.0 % (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 $10,695 and $16,198 as of December 31, 2019 and December 31, 2018, 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 December 31, 2019 and allocated up to $18,000 in coverage as of December 31, 2018 for this customer with a $400 deductible and 10% retention.
Schedule of Percentage Breakdown of Net Accounts Receivable by Aging Category by Invoice Due Date	The following table sets forth the percentage breakdown of the Company’s net accounts receivable (gross accounts receivable net of allowances) by aging category by invoice due date as of December 31, 2019 and December 31, 2018. As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Net accounts receivable by aging category $ % $ % Held and Unbilled $ 294 0.8 % $ 80 0.2 % Aged 0-90 days 33,427 97.4 % 36,245 97.9 % Aged 91-180 days 343 1.0 % 425 1.1 % Aged 181-365 days 261 0.8 % 234 0.6 % Aged over 365 days — 0.0 % 57 0.2 % Total net accounts receivable $ 34,325 100.0 % $ 37,041 100.0 %
Schedule of Allowances for Accounts Receivable	The following table sets forth the accounts receivable allowances as of December 31, 2019 and December 31, 2018: As of As of (amounts in thousands) December 31, 2019 December 31, 2018 Allowances - accounts receivable $ % $ % Doubtful accounts (1) $ 205 0.6 % $ 693 1.8 % Rental revenue adjustments (1) 411 1.1 % 438 1.1 % Sales returns 1,163 3.2 % 890 2.3 % Total allowances - accounts receivable $ 1,779 4.9 % $ 2,021 5.2 %
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 70.2% and 74.8% of the non-U.S. revenue for the years ended December 31, 2019 and 2018, respectively, were invoiced in Euros. A breakdown of the Company’s revenue from U.S. and non-U.S. sources for the years ended December 31, 2019, 2018 and 2017, respectively, is as follows: Years ended December 31, (amounts in thousands) 2019 2018 2017 U.S. revenue $ 283,983 $ 280,778 $ 193,919 Non-U.S. revenue 77,960 77,333 55,519 Total revenue $ 361,943 $ 358,111 $ 249,438
Schedule of Inventories	Inventories that are considered current consist of the following: December 31, (amounts in thousands) 2019 2018 Raw materials and work-in-progress $ 31,676 $ 24,980 Finished goods 5,174 2,756 Less: reserves (1,186 ) (665 ) Inventories, net $ 35,664 $ 27,071
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 years ended December 31, 2019, 2018 and 2017, respectively. Years ended December 31, (amounts in thousands) 2019 2018 2017 Rental equipment $ 6,253 $ 7,567 $ 9,835 Other property and equipment 3,421 2,463 1,960 Total depreciation and amortization $ 9,674 $ 10,030 $ 11,795
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 December 31, 2019 and 2018, respectively. (amounts in thousands) December 31, Property and equipment 2019 2018 Rental equipment, net of allowances of $395 and $594, respectively $ 39,308 $ 43,038 Other property and equipment 24,986 21,596 Property and equipment 64,294 64,634 Accumulated depreciation Rental equipment 30,984 31,813 Other property and equipment 13,872 10,480 Accumulated depreciation 44,856 42,293 Property and equipment, net Rental equipment, net of allowances of $395 and $594, respectively 8,324 11,225 Other property and equipment 11,114 11,116 Property and equipment, net $ 19,438 $ 22,341
Computation of Earnings Per Share	The computation of EPS is as follows: Years ended December 31, (amounts in thousands, except share and per share amounts) 2019 2018 2017 Numerator—basic and diluted: Net income $ 20,950 $ 51,845 $ 21,002 Denominator: Weighted-average common shares - basic common stock (1) 21,821,104 21,266,696 20,683,807 Weighted-average common shares - diluted common stock 22,241,064 22,514,513 21,897,988 Net income per share - basic common stock $ 0.96 $ 2.44 $ 1.02 Net income per share - diluted common stock $ 0.94 $ 2.30 $ 0.96 Denominator calculation from basic to diluted: Weighted-average common shares - basic common stock (1) 21,821,104 21,266,696 20,683,807 Stock options and other dilutive awards 419,960 1,247,817 1,214,181 Weighted-average common shares - diluted common stock 22,241,064 22,514,513 21,897,988 Shares excluded from diluted weighted-average shares: Stock options 53,888 — 37,249 Restricted stock units and restricted stock awards 169,305 39,330 26,064 Shares excluded from diluted weighted-average shares 223,193 39,330 63,313 (1) Unvested restricted stock units and restricted stock awards are not included as shares outstanding in the calculation of basic earnings per share. Vested restricted stock units and restricted stock awards are included in basic earnings 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 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.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Summary of Purchase Price Allocation for Acquisition	The following table summarizes the purchase price allocation for the acquisition of New Aera: (amounts in thousands) 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 twelve months ended December 31, 2019 and the twelve months ended December 31, 2018 presents the revenue and net income assuming the acquisition of New Aera had occurred as of January 1, 2018. Twelve months ended December 31, (amounts in thousands) 2019 2018 Total revenue $ 361,953 $ 358,134 Net income $ 13,256 $ 41,498

Goodwill and Other Identifiab_2

Goodwill and Other Identifiable Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Amount of Goodwill	The changes in the carrying amount of goodwill for the years ended December 31, 2019 and 2018 were as follows: (amounts in thousands) Balance as of December 31, 2017 $ 2,363 Translation adjustment (106 ) Balance as of December 31, 2018 $ 2,257 Translation adjustment (45 ) Acquisition 30,742 Balance as of December 31, 2019 $ 32,954
Summary of Changes in Net Carrying Values of Intangibles	The following tables represent the changes in net carrying values of the intangibles as of the respective dates: Average estimated Gross (amounts in thousands) 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 Average estimated Gross (amounts in thousands) useful lives carrying Accumulated December 31, 2018 (in years) amount amortization Net amount Licenses 10 $ 185 $ 155 $ 30 Patents and websites 5 4,164 1,640 2,524 Customer relationships 4 1,373 572 801 Non-compete agreement 2.3 229 154 75 Commercials 2-3 633 308 325 Total $ 6,584 $ 2,829 $ 3,755
Schedule of Annual Estimated Amortization Expense	Annual estimated amortization expense for each of the succeeding fiscal years is as follows: December 31, (amounts in thousands) 2019 2020 $ 8,970 2021 8,680 2022 8,367 2023 7,792 2024 7,788 Thereafter 35,936 Total $ 77,533

Current Liabilities (Tables)

Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2019
Payables And Accruals [Abstract]
Schedule of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses as of December 31, 2019 and 2018 consisted of the following: December 31, (amounts in thousands) 2019 2018 Accounts payable $ 16,399 $ 13,720 Accrued inventory (in-transit and unvouchered receipts) and trade payables 11,124 9,597 Accrued purchasing card liability 1,675 2,089 Accrued franchise, sales and use taxes 713 518 Other accrued expenses 819 862 Accounts payable and accrued expenses $ 30,730 $ 26,786
Schedule of Accrued Payroll	Accrued payroll as of December 31, 2019 and 2018 consisted of the following: December 31, (amounts in thousands) 2019 2018 Accrued bonuses $ 87 $ 4,780 Accrued wages and other payroll related items 3,158 3,494 Accrued vacation 2,169 1,959 Accrued employee stock purchase plan deductions 801 1,174 Accrued payroll $ 6,215 $ 11,407

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
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: (amounts in thousands) Twelve months ended December 31, 2019 Cash paid for operating lease liabilities $ 2,486 Operating lease cost 2,269 Non-cash right-of-use assets obtained in exchange for new operating lease obligations 7,855 Weighted-average remaining lease term 2.6 years Weighted-average discount rate 3.8 %
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities due in the 12-month period ending December 31, 2020 $ 2,228 2021 1,604 2022 1,284 2023 1,217 2024 917 Thereafter — 7,250 Less imputed interest (534 ) Total lease liabilities $ 6,716 Operating lease liability - current $ 2,014 Operating lease liability - noncurrent 4,702 Total lease liabilities $ 6,716
Future Minimum Payments under Operating Leases Having Initial or Remaining Non-cancelable Lease Terms in Excess of One Year	As of December 31, 2018, prior to the adoption of Topic 842, future minimum payments under operating leases having initial or remaining non-cancelable lease terms in excess of one year were as follows: (amounts in thousands) Operating leases (1) 2019 $ 2,450 2020 2,212 2021 1,593 2022 1,273 2023 1,215 Thereafter 917 Total minimum payments $ 9,660 (1) Includes future minimum payments for leases which have not yet commenced.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Components of Income Before Provision for Income Taxes	The components of the Company’s income before provision for income taxes are as follows: Years ended December 31, (amounts in thousands) 2019 2018 2017 United States $ 22,553 $ 40,245 $ 29,121 Foreign 1,719 210 535 Income before provision for income taxes $ 24,272 $ 40,455 $ 29,656
Components of Provisions for Income Taxes	The provision for income taxes consists of the following: Years ended December 31, (amounts in thousands) 2019 2018 2017 Current tax expense (benefit) Federal $ (330 ) $ — $ 245 State 136 (40 ) 240 Foreign 560 171 206 Total current tax expense 366 131 691 Deferred tax expense (benefit) Federal 3,497 (9,774 ) 8,709 State (396 ) (1,630 ) 92 Foreign (145 ) (117 ) (71 ) Total deferred tax expense (benefit) 2,956 (11,521 ) 8,730 Tax benefit for change in valuation allowance — — (767 ) Total deferred tax expense (benefit), net 2,956 (11,521 ) 7,963 Income tax expense (benefit) $ 3,322 $ (11,390 ) $ 8,654
Components of Deferred Tax Assets and Liabilities	The components of deferred tax assets and liabilities consist of the following: (amounts in thousands) As of December 31, Deferred tax assets (liabilities) 2019 2018 Accrued expenses $ 7,981 $ 8,033 Net operating loss and credit carryforward 20,087 19,805 Allowance, reserves and other 1,984 3,490 Stock-based compensation 3,257 3,253 Lease liability 1,627 — Deferred tax assets 34,936 34,581 Property, plant, and equipment (2,961 ) (4,683 ) Intangible amortization (16,192 ) — Right-of-use asset (1,418 ) — Deferred tax liabilities (20,571 ) (4,683 ) Total $ 14,365 $ 29,898
Reconciliation of the Federal Statutory Income Tax Rate to the Effective Income Tax Rate	Reconciliation of the federal statutory income tax rate to the effective income tax rate for the years ended December 31, 2019, 2018 and 2017 is as follows: Years ended December 31, 2019 2018 2017 U.S. Statutory rate 21.00 % 21.00 % 34.00 % State income taxes, net of federal benefit 3.70 (3.73 ) 0.37 Stock-based compensation (0.81 ) (45.01 ) (30.40 ) Change in valuation allowance — — (2.59 ) R&D credit, net of reserve (8.97 ) (1.39 ) (1.43 ) Expiration of net operating losses — — 2.76 Effect of U.S tax law change — — 25.55 Other (1.24 ) 0.98 0.92 Effective income tax rate 13.68 % (28.15)% 29.18 %
Summary of Reconciliation of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of unrecognized tax benefit is as follows: (amounts in thousands) December 31, Reconciliation of liability for unrecognized tax benefits 2019 2018 2017 Balance at beginning of period $ 1,294 $ 1,062 $ 934 Additions based on tax positions related to current year 595 232 128 Balance at end of period $ 1,889 $ 1,294 $ 1,062

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Summary of Stock Options Activity	The activity for stock options under the Company’s stock plans for the years ended December 31, 2019, 2018 and 2017 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, 2016 2,355,527 $0.60-$58.95 $ 28.22 5.42 $ 38.95 Granted 64,498 83.30 83.30 Exercised (520,393 ) 0.60-58.95 24.16 Forfeited (63,173 ) 24.52-58.95 43.74 Expired (33 ) 8.70 8.70 Outstanding as of December 31, 2017 1,836,426 0.60-83.30 30.77 4.58 88.31 Vested and exercisable as of December 31, 2017 1,176,504 0.60-83.30 24.33 4.39 94.75 Vested and expected to vest as of December 31, 2017 1,792,871 0.60-83.30 30.50 4.58 88.58 Outstanding as of December 31, 2017 1,836,426 0.60-83.30 30.77 4.58 88.31 Granted — — — Exercised (708,319 ) 0.60-58.95 24.22 Forfeited (771 ) 24.52-44.19 28.24 Expired — — — Outstanding as of December 31, 2018 1,127,336 0.75-83.30 34.89 3.84 89.28 Vested and exercisable as of December 31, 2018 851,039 0.75-83.30 32.12 3.75 92.05 Vested and expected to vest as of December 31, 2018 1,109,280 0.75-83.30 34.75 3.84 89.42 Outstanding as of December 31, 2018 1,127,336 0.75-83.30 34.89 3.84 89.28 Granted — — — Exercised (109,291 ) 0.75-58.95 28.45 Forfeited (37,161 ) 38.54-58.95 44.58 Expired — — — Outstanding as of December 31, 2019 980,884 0.75-83.30 35.24 2.84 34.07 Vested and exercisable as of December 31, 2019 929,825 0.75-83.30 34.73 2.81 34.64 Vested and expected to vest as of December 31, 2019 977,589 $0.75-$83.30 $ 35.21 2.84 $ 34.11
Summary of Restricted Stock Activity	Stock Awards activity for the years ended December 31, 2019 and December 31, 2018 are 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, 2016 — — — $ — Granted 42,028 13,109 55,137 90.05 Vested — — — — Forfeited/canceled — — — — Unvested restricted stock units as of December 31, 2017 (1) 42,028 13,109 55,137 $ 90.05 Unvested and expected to vest restricted stock units outstanding as of December 31, 2017 48,589 $ 89.95 Unvested restricted stock units as of December 31, 2017 42,028 13,109 55,137 $ 90.05 Granted 31,877 — 31,877 143.50 Vested (13,742 ) (4,370 ) (18,112 ) 89.35 Forfeited/canceled (1,574 ) — (1,574 ) 106.55 Unvested restricted stock units as of December 31, 2018 (1) 58,589 8,739 67,328 $ 115.16 Unvested and expected to vest restricted stock units outstanding as of December 31, 2018 62,504 $ 115.98 Unvested restricted stock units as of December 31, 2018 58,589 8,739 67,328 $ 115.16 Granted 87,902 — 87,902 75.56 Vested (24,680 ) (4,366 ) (29,046 ) 123.53 Forfeited/canceled (12,835 ) (1,239 ) (14,074 ) 102.89 Unvested restricted stock units as of December 31, 2019 (1) 108,976 3,134 112,110 $ 83.48 Unvested and expected to vest restricted stock units outstanding as of December 31, 2019 103,087 $ 83.22 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, 2016 — — — $ — Granted 20,789 20,785 41,574 91.52 Vested — — — — Forfeited/canceled — — — — Unvested restricted stock awards outstanding as of December 31, 2017 (1) 20,789 20,785 41,574 $ 91.52 Unvested and expected to vest restricted stock awards outstanding as of December 31, 2017 34,051 $ 91.52 Unvested restricted stock awards outstanding as of December 31, 2017 20,789 20,785 41,574 $ 91.52 Granted 22,645 33,964 56,609 130.89 Vested (6,497 ) (6,928 ) (13,425 ) 91.52 Forfeited/canceled — — — — Unvested restricted stock awards outstanding as of December 31, 2018 (1) 36,937 47,821 84,758 $ 115.80 Unvested and expected to vest restricted stock awards outstanding as of December 31, 2018 65,773 $ 115.85 Unvested restricted stock awards outstanding as of December 31, 2018 36,937 47,821 84,758 $ 115.80 Granted 54,853 40,166 95,019 86.10 Vested (13,627 ) (15,732 ) (29,359 ) 115.37 Forfeited/canceled (7,093 ) (9,627 ) (16,720 ) 109.11 Unvested restricted stock awards outstanding as of December 31, 2019 (1) 71,070 62,628 133,698 $ 95.74 Unvested and expected to vest restricted stock awards outstanding as of December 31, 2019 79,473 $ 90.31 (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 years ended December 31, 2019, 2018 and 2017, was as follows: (amounts in thousands) Years ended December 31, Stock-based compensation expense by type of award: 2019 2018 2017 Stock option plan awards $ 2,977 $ 6,015 $ 7,652 Restricted stock units and restricted stock awards 5,413 5,890 1,447 Employee stock purchase plan 739 885 541 Total stock-based compensation expense $ 9,129 $ 12,790 $ 9,640 For the years ended December 31, 2019, 2018 and 2017, 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: Years ended December 31, (amounts in thousands) 2019 2018 2017 Cost of revenue $ 890 $ 1,060 $ 845 Research and development 1,100 1,314 1,015 Sales and marketing 1,755 2,355 1,558 General and administrative 5,384 8,061 6,222 Total stock-based compensation expense $ 9,129 $ 12,790 $ 9,640
Assumptions Applied to Estimate Fair Value of Stock Option Awards	The following table displays the assumptions that have been applied to estimate the fair value of stock option awards on the date of grant using the Black-Scholes option pricing model. During 2019 and 2018, the Company did not grant any stock option awards. 2017 Expected term (years) 3.54-4.00 Risk free interest rate 1.65-1.73% Expected dividend yield None Volatility 41.61-42.15%
Assumptions Applied to Estimate Fair Value of Shares Issued Under ESPP	The following table displays the assumptions that have been applied to estimate the fair value of the Company’s shares to be issued under the ESPP using the Black-Scholes option pricing model. 2019 2018 2017 Expected term (years) 0.50 0.50 0.50 Risk free interest rate 1.75-2.53% 1.63-2.46% 1.15-1.63% Expected dividend yield None None None Volatility 44.00-47.00% 37.34-44.00% 42.35-45.34%

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2019
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. At December 31, 2019, the minimum aggregate payments due under specified non-cancelable contractual obligations Non-cancelable contractual (amounts in thousands) obligations 2020 $ 578 2021 457 2022 — 2023 — 2024 — Thereafter — Total $ 1,035
Schedule of Changes in Aggregate Product Warranty Liabilities	The following table identifies the changes in the Company’s aggregate product warranty liabilities for the twelve-month periods ended December 31, 2019, 2018 and 2017, respectively: December 31, (amounts in thousands) 2019 2018 2017 Product warranty liability at beginning of period $ 9,530 $ 6,171 $ 3,480 Accruals for warranties issued 8,131 7,693 5,275 Adjustments related to preexisting warranties (including changes in estimates) 1,433 90 200 Settlements made (in cash or in kind) (6,523 ) (4,424 ) (2,784 ) Product warranty liability at end of period $ 12,571 $ 9,530 $ 6,171

Quarterly Summary of Informat_2

Quarterly Summary of Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Summary of Unaudited Quarterly Statements of Income Data	The following table sets forth the Company’s unaudited quarterly statements of income data in dollars for each of the eight quarters in the period ended December 31, 2019. The Company has prepared the quarterly statements of income data on a basis consistent with the audited financial statements. In the opinion of management, the financial information reflects all adjustments, consisting only of normal recurring adjustments, which the Company considers necessary for a fair presentation of this data. The results of historical periods are not necessarily indicative of the results of operations for any future period. (amounts in thousands, except share and per share amounts) Quarterly Results 2019 Q1 March Q2 June Q3 September Q4 December Total revenue $ 90,202 $ 101,063 $ 91,761 $ 78,917 Gross profit 44,409 50,215 43,315 33,922 Income (loss) before provision (benefit) for income taxes 6,072 13,684 8,753 (4,237 ) Provision (benefit) for income taxes 770 3,524 1,890 (2,862 ) Net income (loss) 5,302 10,160 6,863 (1,375 ) Net income (loss) per share attributable to common stockholders: Basic $ 0.24 $ 0.47 $ 0.31 $ (0.06 ) Diluted (1) $ 0.24 $ 0.45 $ 0.31 $ (0.06 ) Weighted-average number of shares used in calculating net income (loss) per share attributable to common stockholders: Basic common shares 21,750,305 21,815,634 21,840,473 21,878,004 Diluted common shares 22,534,885 22,359,679 22,191,688 21,878,004 (1) Due to net loss for period Q4 December, dilutive loss per share is the same as basic. (amounts in thousands, except share and per share amounts) Quarterly Results 2018 Q1 March Q2 June Q3 September Q4 December Total revenue $ 79,051 $ 97,238 $ 95,291 $ 86,531 Gross profit 37,727 48,470 48,813 43,570 Income before benefit for income taxes 9,687 13,646 11,299 5,823 Benefit for income taxes (1,071 ) (964 ) (5,133 ) (4,222 ) Net income 10,758 14,610 16,432 10,045 Net income per share attributable to common stockholders: Basic $ 0.51 $ 0.69 $ 0.77 $ 0.47 Diluted $ 0.48 $ 0.65 $ 0.73 $ 0.44 Weighted-average number of shares used in calculating net income per share attributable to common stockholders: Basic common shares 21,026,154 21,172,170 21,324,256 21,544,202 Diluted common shares 22,295,213 22,503,749 22,659,052 22,600,038

Nature of Business - Additional

Nature of Business - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019Product
Inogen Europe Holding B.V.
Nature Of Business [Line Items]
Date of incorporation of subsidiary	Apr. 13, 2017
Minimum | Inogen One
Nature Of Business [Line Items]
Number of portable oxygen concentrators	774,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019USD ($)CustomerSegment	Dec. 31, 2018USD ($)Customer	Dec. 31, 2017USD ($)Customer	Jan. 01, 2019USD ($)
Significant Accounting Policies [Line Items]
Standard warranty period offered	3 years
Cash payments received in advance of satisfying performance obligations	$ 8,757,000	$ 6,909,000
Performance obligation partially offset of revenue recognized	5,903,000	2,855,000
Deferred capped rental revenue	$ 0	0
Rental revenue earned	30 days
Accounts receivable, net	$ 34,325,000	37,041,000
Unbilled Receivables	590,000	589,000
Increase in provision for bad debt and revenue adjustments related to prior years	$ 611,000	$ 1,757,000
Percentage of Non-US revenue invoiced in Euros	70.20%	74.80%
Transfer of inventory to rental equipment	$ 1,043,000	$ 1,187,000	$ 1,055,000
Salvage value of expenditures for additions, improvements and replacements	0
Repairs and maintenance expense	2,854,000	2,289,000	2,385,000
Depreciation and amortization	9,674,000	10,030,000	11,795,000
Impairments of long-lived assets	0	0
Goodwill impairment loss	0	0
Advertising costs	$ 40,251,000	30,755,000	12,511,000
Number of operating segments | Segment	1
Number of reportable segments | Segment	1
Operating lease right-of-use asset	$ 5,855,000			$ 6,418,000
Operating lease liabilities	2,014,000
ASU 2016-02
Significant Accounting Policies [Line Items]
Operating lease right-of-use asset	6,400,000
Operating lease liabilities	6,400,000
Cumulative effect adjustment on retained earnings	0
Construction in Process and Computer Software or Development Cost
Significant Accounting Policies [Line Items]
Depreciation and amortization	0	0	$ 0
Other Noncurrent Assets
Significant Accounting Policies [Line Items]
Noncurrent inventories expected to be realized or consumed	1,076,000	1,085,000
Customer Concentration Risk | Customer One
Significant Accounting Policies [Line Items]
Accounts receivable, net	10,695,000	16,198,000
Customer Concentration Risk | Customer Two
Significant Accounting Policies [Line Items]
Accounts receivable, net	$ 5,228,000	$ 4,155,000
Sales Revenue, Net | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Number of customers | Customer	0	1	1
Net Accounts Receivable | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Number of customers | Customer	2	2
Raw materials | Supplier Concentration Risk | Vendor one
Significant Accounting Policies [Line Items]
Concentration risk, percentage	23.20%	20.00%
Raw materials | Supplier Concentration Risk | Vendor two
Significant Accounting Policies [Line Items]
Concentration risk, percentage	13.90%	11.90%
Raw materials | Supplier Concentration Risk | Vendor three
Significant Accounting Policies [Line Items]
Concentration risk, percentage	9.40%	10.20%
Fair Value Measurements Recurring | Level 3 | Maximum
Significant Accounting Policies [Line Items]
Earnout Liability	$ 31,400,000
Forward Contracts
Significant Accounting Policies [Line Items]
Payable	514,000
Accounts receivable, net		$ 472,000
Lifetime Warranties | Direct-to-Consumer
Significant Accounting Policies [Line Items]
Sales revenue	$ 17,728,000	$ 14,874,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Sales Revenue Disaggregated by Sales Channel and Geographic Region (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Total sales revenue	$ 340,546	$ 336,015	$ 225,492
Business to Business | Domestic
Disaggregation Of Revenue [Line Items]
Total sales revenue	106,428	116,581	83,390
Business to Business | International
Disaggregation Of Revenue [Line Items]
Total sales revenue	77,960	77,333	55,519
Direct-to-Consumer | Domestic
Disaggregation Of Revenue [Line Items]
Total sales revenue	$ 156,158	$ 142,101	$ 86,583

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Fair Value Assets Measured on Recurring Basis for Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 198,037	$ 196,634
Fair Value Measurements Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Adjusted cost	209,086	240,358
Gross unrealized gains (losses)	8	(9)
Fair value	209,094	240,349
Cash and cash equivalents	198,037	196,634
Marketable securities	11,057	43,715
Fair Value Measurements Recurring | Cash
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Adjusted cost	51,560	33,671
Fair value	51,560	33,671
Cash and cash equivalents	51,560	33,671
Fair Value Measurements Recurring | Level 1 | Money Market Accounts
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Adjusted cost	146,477	158,438
Fair value	146,477	158,438
Cash and cash equivalents	146,477	158,438
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	13,629
Gross unrealized gains (losses)	2	(16)
Fair value	2,013	13,613
Marketable securities	2,013	13,613
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	34,620
Gross unrealized gains (losses)	6	7
Fair value	9,044	34,627
Cash and cash equivalents		4,525
Marketable securities	$ 9,044	$ 30,102

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Summary of Estimated Fair Value of Company's Investments in Marketable Securities Classified by Contractual Maturity Date (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Available For Sale Securities [Abstract]
Due within one year	$ 11,057
Total	$ 11,057	$ 43,715

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Summary of Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 310,424	$ 227,041	$ 182,088
Other comprehensive income (loss)	(811)	452	307
Ending Balance	344,621	310,424	227,041
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	394	363
Other comprehensive income (loss)	(123)	31
Ending Balance	271	394	363
Unrealized Gains (Losses) on Marketable Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(17)
Other comprehensive income (loss)	6	17
Ending Balance	6		(17)
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	330	(74)
Other comprehensive income (loss)	(694)	404
Ending Balance	(364)	330	(74)
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	724	272	(35)
Other comprehensive income (loss)	(811)	452	307
Ending Balance	$ (87)	$ 724	$ 272

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Summary of Quantitative Information about Level 3 Inputs for Fair Value Measurement of Earnout Liability (Details) - Level 3	Dec. 31, 2019	Aug. 09, 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	13	12.50
20-Year Risk Free Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earnout liability, measurement input	2.25	2.03
Market Price of Risk
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Earnout liability, measurement input	10	9

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Summary of Reconciliation of Earnout Liability Measured and Carried Fair Value on a Recurring Basis (Details) - Fair Value Measurements Recurring $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Addition for acquisition	$ 25,749
Change in fair value	810
Ending Balance	$ 26,559

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Summary of Cash, Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Cash and cash equivalents
Cash	$ 51,560	$ 33,671
Money market accounts	146,477	158,438
U.S. Treasury securities		4,525
Total cash and cash equivalents	198,037	196,634
Marketable securities
Marketable securities	11,057	43,715
Corporate Bonds
Marketable securities
Marketable securities	2,013	13,613
U.S. Treasury Securities
Marketable securities
Marketable securities	$ 9,044	$ 30,102

Summary of Significant Accou_12

Summary of Significant Accounting Policies - Schedule of Gross Accounts Receivable Balance Concentrations by Major Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Gross accounts receivable	$ 36,104	$ 39,062
Gross accounts receivable, percentage	100.00%	100.00%
Rental
Accounts Notes And Loans Receivable [Line Items]
Gross accounts receivable	$ 3,003	$ 3,406
Gross accounts receivable, percentage	8.30%	8.70%
Business To Business And Other Receivables
Accounts Notes And Loans Receivable [Line Items]
Gross accounts receivable	$ 33,101	$ 35,656
Gross accounts receivable, percentage	91.70%	91.30%

Summary of Significant Accou_13

Summary of Significant Accounting Policies - Schedule of Net Accounts Receivable Balance Concentrations by Major Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Net accounts receivable	$ 34,325	$ 37,041
Net accounts receivable, percentage	100.00%	100.00%
Rental
Accounts Notes And Loans Receivable [Line Items]
Net accounts receivable	$ 2,464	$ 2,413
Net accounts receivable, percentage	7.20%	6.50%
Business To Business And Other Receivables
Accounts Notes And Loans Receivable [Line Items]
Net accounts receivable	$ 31,861	$ 34,628
Net accounts receivable, percentage	92.80%	93.50%

Summary of Significant Accou_14

Summary of Significant Accounting Policies - Schedule of Net Accounts Receivable Balance Concentrations by Major Category (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2019USD ($)Customer	Dec. 31, 2018USD ($)Customer
Accounts Notes And Loans Receivable [Line Items]
Gross accounts receivable	$ 36,104,000	$ 39,062,000
Customer Concentration Risk | Business To Business Receivables
Accounts Notes And Loans Receivable [Line Items]
Number of customers | Customer	1	1
Gross accounts receivable	$ 10,695,000	$ 16,198,000
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	$ 18,000,000

Summary of Significant Accou_15

Summary of Significant Accounting Policies - Schedule of Net Accounts Receivable Balance by Aging Category by Invoice Due Date (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net	$ 34,325	$ 37,041
Net accounts receivable, percentage	100.00%	100.00%
Held And Unbilled
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net	$ 294	$ 80
Net accounts receivable, percentage	0.80%	0.20%
Aged 0-90 Days
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net	$ 33,427	$ 36,245
Net accounts receivable, percentage	97.40%	97.90%
Aged 91-180 Days
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net	$ 343	$ 425
Net accounts receivable, percentage	1.00%	1.10%
Aged 181-365 Days
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net	$ 261	$ 234
Net accounts receivable, percentage	0.80%	0.60%
Aged Over 365 Days
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, net		$ 57
Net accounts receivable, percentage	0.00%	0.20%

Summary of Significant Accou_16

Summary of Significant Accounting Policies - Schedule of Allowances for Accounts Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Allowances - accounts receivable
Doubtful accounts	$ 205	$ 693
Rental revenue adjustments	411	438
Sales returns	1,163	890
Total allowances - accounts receivable	$ 1,779	$ 2,021
Doubtful accounts, percentage	0.60%	1.80%
Rental revenue adjustments, percentage	1.10%	1.10%
Sales returns, percentage	3.20%	2.30%
Total allowances - accounts receivable, percentage	4.90%	5.20%

Summary of Significant Accou_17

Summary of Significant Accounting Policies - Breakdown of the Company Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Revenues	$ 78,917	$ 91,761	$ 101,063	$ 90,202	$ 86,531	$ 95,291	$ 97,238	$ 79,051	$ 361,943	$ 358,111	$ 249,438
U.S. revenue
Concentration Risk [Line Items]
Revenues									283,983	280,778	193,919
Non-U.S. revenue
Concentration Risk [Line Items]
Revenues									$ 77,960	$ 77,333	$ 55,519

Summary of Significant Accou_18

Summary of Significant Accounting Policies - Schedule of Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials and work-in-progress	$ 31,676	$ 24,980
Finished goods	5,174	2,756
Less: reserves	(1,186)	(665)
Inventories, net	$ 35,664	$ 27,071

Summary of Significant Accou_19

Summary of Significant Accounting Policies - Computation of Depreciation and Amortization Using Straight Line Method Over Estimated Useful Lives of Assets (Details)	12 Months Ended
	Dec. 31, 2019
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

Summary of Significant Accou_20

Summary of Significant Accounting Policies - Summary of Depreciation and Amortization Expense of Rental Equipment and Other Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Depreciation	$ 6,253	$ 7,567	$ 9,835
Depreciation and amortization	9,674	10,030	11,795
Rental equipment
Property Plant And Equipment [Line Items]
Depreciation	6,253	7,567	9,835
Other property and equipment
Property Plant And Equipment [Line Items]
Depreciation and amortization	$ 3,421	$ 2,463	$ 1,960

Summary of Significant Accou_21

Summary of Significant Accounting Policies - Summary of Property Plant and Equipment and Rental Equipment with Associated Accumulated Depreciation (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment	$ 64,294	$ 64,634
Accumulated depreciation	44,856	42,293
Property and equipment, net	19,438	22,341
Rental equipment
Property Plant And Equipment [Line Items]
Property and equipment	39,308	43,038
Accumulated depreciation	30,984	31,813
Property and equipment, net	8,324	11,225
Other property and equipment
Property Plant And Equipment [Line Items]
Property and equipment	24,986	21,596
Accumulated depreciation	13,872	10,480
Property and equipment, net	$ 11,114	$ 11,116

Summary of Significant Accou_22

Summary of Significant Accounting Policies - Summary of Property Plant and Equipment and Rental Equipment with Associated Accumulated Depreciation (Parenthetical) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Rental equipment, allowance	$ 395	$ 594

Summary of Significant Accou_23

Summary of Significant Accounting Policies - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator—basic and diluted:
Net income	$ (1,375)	$ 6,863	$ 10,160	$ 5,302	$ 10,045	$ 16,432	$ 14,610	$ 10,758	$ 20,950	$ 51,845	$ 21,002
Denominator:
Weighted-average common shares - basic common stock	21,878,004	21,840,473	21,815,634	21,750,305	21,544,202	21,324,256	21,172,170	21,026,154	21,821,104	21,266,696	20,683,807
Weighted-average common shares - diluted common stock	21,878,004	22,191,688	22,359,679	22,534,885	22,600,038	22,659,052	22,503,749	22,295,213	22,241,064	22,514,513	21,897,988
Net income per share - basic common stock	$ (0.06)	$ 0.31	$ 0.47	$ 0.24	$ 0.47	$ 0.77	$ 0.69	$ 0.51	$ 0.96	$ 2.44	$ 1.02
Net income per share - diluted common stock	$ (0.06)	$ 0.31	$ 0.45	$ 0.24	$ 0.44	$ 0.73	$ 0.65	$ 0.48	$ 0.94	$ 2.30	$ 0.96
Denominator calculation from basic to diluted:
Weighted-average common shares - basic common stock	21,878,004	21,840,473	21,815,634	21,750,305	21,544,202	21,324,256	21,172,170	21,026,154	21,821,104	21,266,696	20,683,807
Stock options and other dilutive awards									419,960	1,247,817	1,214,181
Weighted-average common shares - diluted common stock	21,878,004	22,191,688	22,359,679	22,534,885	22,600,038	22,659,052	22,503,749	22,295,213	22,241,064	22,514,513	21,897,988
Shares excluded from diluted weighted-average shares:
Shares excluded from diluted weighted-average shares									223,193	39,330	63,313
Stock options
Shares excluded from diluted weighted-average shares:
Shares excluded from diluted weighted-average shares									53,888		37,249
Restricted stock units and restricted stock awards
Shares excluded from diluted weighted-average shares:
Shares excluded from diluted weighted-average shares									169,305	39,330	26,064

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) - New Aera, Inc. - USD ($)	Aug. 09, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Cash paid at closing	$ 70,523,000
Acquisition-related expenses		$ 784,000
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	Dec. 31, 2019	Aug. 09, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 32,954		$ 2,257	$ 2,363
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. - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Total revenue	$ 361,953	$ 358,134
Net income	$ 13,256	$ 41,498

Goodwill and Other Identifiab_3

Goodwill and Other Identifiable Intangible Assets - Schedule of Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning Balance	$ 2,257	$ 2,363
Translation adjustment	(45)	(106)
Acquisition	30,742
Ending Balance	$ 32,954	$ 2,257

Goodwill and Other Identifiab_4

Goodwill and Other Identifiable Intangible Assets - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Impairment of finite lived intangible assets	$ 0	$ 0
Amortization of intangible assets	$ 4,160,000	$ 1,265,000	$ 507,000

Goodwill and Other Identifiab_5

Goodwill and Other Identifiable Intangible Assets - Summary of Changes in Net Carrying Values of Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	$ 84,282	$ 6,584
Accumulated amortization	6,749	2,829
Net amount	$ 77,533	$ 3,755
Technology
Finite Lived Intangible Assets [Line Items]
Average estimated useful lives (in years)	10 years
Gross carrying amount	$ 77,700
Accumulated amortization	2,914
Net amount	$ 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	165	155
Net amount	$ 20	$ 30
Patents And Websites
Finite Lived Intangible Assets [Line Items]
Average estimated useful lives (in years)	5 years	5 years
Gross carrying amount	$ 4,274	$ 4,164
Accumulated amortization	2,308	1,640
Net amount	$ 1,966	$ 2,524
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Average estimated useful lives (in years)	4 years	4 years
Gross carrying amount	$ 1,346	$ 1,373
Accumulated amortization	897	572
Net amount	449	$ 801
Non-Compete Agreement
Finite Lived Intangible Assets [Line Items]
Average estimated useful lives (in years)		2 years 3 months 18 days
Gross carrying amount		$ 229
Accumulated amortization		154
Net amount		75
Commercials
Finite Lived Intangible Assets [Line Items]
Gross carrying amount	777	633
Accumulated amortization	465	308
Net amount	$ 312	$ 325
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

Goodwill and Other Identifiab_6

Goodwill and Other Identifiable Intangible Assets - Schedule of Annual Estimated Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
2020	$ 8,970
2021	8,680
2022	8,367
2023	7,792
2024	7,788
Thereafter	35,936
Net amount	$ 77,533	$ 3,755

Current Liabilities - Schedule

Current Liabilities - Schedule of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accounts payable	$ 16,399	$ 13,720
Accrued inventory (in-transit and unvouchered receipts) and trade payables	11,124	9,597
Accrued purchasing card liability	1,675	2,089
Accrued franchise, sales and use taxes	713	518
Other accrued expenses	819	862
Accounts payable and accrued expenses	$ 30,730	$ 26,786

Current Liabilities - Schedul_2

Current Liabilities - Schedule of Accrued Payroll (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued bonuses	$ 87	$ 4,780
Accrued wages and other payroll related items	3,158	3,494
Accrued vacation	2,169	1,959
Accrued employee stock purchase plan deductions	801	1,174
Accrued payroll	$ 6,215	$ 11,407

Leases - Additional Information

Leases - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 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 right-of-use asset	$ 5,855,000		$ 6,418,000
Operating lease, liability	6,716,000		$ 6,418,000
Operating lease cost	$ 2,269,000
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.
Commercial and 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 commercial and industrial space in Texas will increase annually by two and one-half percent (2.5%) at each annual adjustment date thereafter.
MedSupport Systems B.V.
Lessee Lease Description [Line Items]
Operating lease cost	$ 31,000	$ 33,000
Minimum
Lessee Lease Description [Line Items]
Operating leases, lease term	2 years
Minimum | Corporate Headquarters in California and Commercial and Industrial Space in Texas
Lessee Lease Description [Line Items]
Operating leases, lease term	10 years
Additional operating lease cost	$ 27,215,000
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 Commercial 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) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Cash paid for operating lease liabilities	$ 2,486
Operating lease cost	2,269
Non-cash right-of-use assets obtained in exchange for new operating lease obligations	$ 7,855
Weighted-average remaining lease term	2 years 7 months 6 days
Weighted-average discount rate	3.80%

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019
Maturities of lease liabilities due in the 12-month period ending December 31,
2020	$ 2,228
2021	1,604
2022	1,284
2023	1,217
2024	917
Operating lease liabilities payments due	7,250
Less imputed interest	(534)
Total lease liabilities	6,716	$ 6,418
Operating lease liability - current	2,014
Operating lease liability - noncurrent	4,702
Total lease liabilities	$ 6,716	$ 6,418

Leases - Future Minimum Payment

Leases - Future Minimum Payments under Operating Leases Having Initial or Remaining Non-cancelable Lease Terms in Excess of One Year (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
Operating leases, 2019	$ 2,450
Operating leases, 2020	2,212
Operating leases, 2021	1,593
Operating leases, 2022	1,273
Operating leases, 2023	1,215
Operating leases, Thereafter	917
Operating leases, Total minimum payments	$ 9,660

Income Taxes - Components of In

Income Taxes - Components of Income Before Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
United States									$ 22,553	$ 40,245	$ 29,121
Foreign									1,719	210	535
Income before provision (benefit) for income taxes	$ (4,237)	$ 8,753	$ 13,684	$ 6,072	$ 5,823	$ 11,299	$ 13,646	$ 9,687	$ 24,272	$ 40,455	$ 29,656

Income Taxes - Components of Pr

Income Taxes - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current tax expense (benefit)
Federal									$ (330)		$ 245
State									136	$ (40)	240
Foreign									560	171	206
Total current tax expense									366	131	691
Deferred tax expense (benefit)
Federal									3,497	(9,774)	8,709
State									(396)	(1,630)	92
Foreign									(145)	(117)	(71)
Total deferred tax expense (benefit)									2,956	(11,521)	8,730
Tax benefit for change in valuation allowance											(767)
Total deferred tax expense (benefit), net									2,956	(11,521)	7,963
Income tax expense (benefit)	$ (2,862)	$ 1,890	$ 3,524	$ 770	$ (4,222)	$ (5,133)	$ (964)	$ (1,071)	$ 3,322	$ (11,390)	$ 8,654

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets (liabilities)
Accrued expenses	$ 7,981	$ 8,033
Net operating loss and credit carryforward	20,087	19,805
Allowance, reserves and other	1,984	3,490
Stock-based compensation	3,257	3,253
Lease liability	1,627
Deferred tax assets	34,936	34,581
Property, plant, and equipment	(2,961)	(4,683)
Intangible amortization	(16,192)
Right-of-use asset	(1,418)
Deferred tax liabilities	(20,571)	(4,683)
Total	$ 14,365	$ 29,898

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of the Federal Statutory Income Tax Rate to the Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Abstract]
U.S. Statutory rate	21.00%	21.00%	34.00%
State income taxes, net of federal benefit	3.70%	(3.73%)	0.37%
Stock-based compensation	(0.81%)	(45.01%)	(30.40%)
Change in valuation allowance			(2.59%)
R&D credit, net of reserve	(8.97%)	(1.39%)	(1.43%)
Expiration of net operating losses			2.76%
Effect of U.S tax law change			25.55%
Other	(1.24%)	0.98%	0.92%
Effective income tax rate	13.68%	(28.15%)	29.18%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Corporate tax rate		21.00%	21.00%	34.00%
Provisional net charge related to TCJA	$ 7,578,000
Additional adjustment to provisional amount	0
Unrecognized tax benefits, interest or penalties recognized		$ 0	$ 0	$ 0
Unrecognized tax benefits that, if recognized, would affect the effective tax rate	$ 1,062,000	1,889,000	$ 1,294,000	$ 1,062,000
Research and Development Credit | California
Income Tax Contingency [Line Items]
Research and development credits carryforwards		4,006,000
Federal
Income Tax Contingency [Line Items]
Net operating loss carryforwards		54,883,000
Net operating loss carryforwards, indefinite life		$ 46,426,000
Net operating loss carryforwards expiration, beginning year		2033
Research and development credits carryforwards expiration, beginning year		2022
Federal | Research and Development Credit
Income Tax Contingency [Line Items]
Research and development credits carryforwards		$ 4,511,000
State
Income Tax Contingency [Line Items]
Net operating loss carryforwards		$ 25,679,000
Net operating loss carryforwards expiration, beginning year		2028

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of liability for unrecognized tax benefits
Balance at beginning of period	$ 1,294	$ 1,062	$ 934
Additions based on tax positions related to current year	595	232	128
Balance at end of period	$ 1,889	$ 1,294	$ 1,062

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019USD ($)Voteshares	Dec. 31, 2018USD ($)shares	Dec. 31, 2017USD ($)shares
Class Of Stock [Line Items]
Number of voting rights per share of common stock | Vote	1
Preferred stock, shares authorized	10,000,000
Preferred stock, shares issued		0
Preferred stock, shares outstanding		0
Dividends declared | $	$ 0	$ 0	$ 0
Total intrinsic value of options exercised | $	7,910,000	98,743,000	33,931,000
Stock-based compensation, unrecognized expense, nonvested granted awards | $	$ 691,000
Amount expected to recognized over weighted-average period	3 months 18 days
Total weighted average fair value of stock options granted | $			8,929,000
401(k) Retirement Savings Plan
Class Of Stock [Line Items]
Defined benefit plan, contributed by employer net of forfeitures | $	$ 871,000	$ 865,000	$ 557,000
Stock options
Class Of Stock [Line Items]
Rate of reduced stock-based compensation expense for estimated forfeiture	7.30%	7.30%	7.30%
Time based restricted stock units
Class Of Stock [Line Items]
Vesting period	4 years
Grants of units unvested	87,902	31,877	42,028
Time based restricted stock awards
Class Of Stock [Line Items]
Vesting period	4 years
Grants of units unvested	54,853	22,645	20,789
Performance and time based restricted stock awards
Class Of Stock [Line Items]
Vesting period	3 years
Grants of units unvested	40,166	33,964	20,785
Performance and time based restricted stock units
Class Of Stock [Line Items]
Vesting period	3 years
Grants of units unvested			13,109
Restricted stock units and restricted stock awards
Class Of Stock [Line Items]
Amount expected to recognized over weighted-average period	2 years 8 months 12 days
Unrecognized compensation cost related to unvested employee excluding estimated forfeitures | $	$ 12,829,000
Rate of reduced stock-based compensation expense for estimated forfeiture	4.40%	4.70%	6.00%
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	141,986
Number of equity awards available for grant	0
2014 Plan
Class Of Stock [Line Items]
Stock option shares outstanding	1,064,545
Number of equity awards available for grant	1,807,572
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	698,632
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	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class Of Stock [Line Items]
Stock Options Outstanding, Beginning balance	1,127,336	1,836,426	2,355,527
Stock Options, Granted			64,498
Stock Options, Exercised	(109,291)	(708,319)	(520,393)
Stock Options, Forfeited	(37,161)	(771)	(63,173)
Stock Options, Expired			(33)
Stock Options Outstanding, Ending balance	980,884	1,127,336	1,836,426	2,355,527
Stock Options, Vested and exercisable	929,825	851,039	1,176,504
Stock Options, Vested and expected to vest	977,589	1,109,280	1,792,871
Price per share, Granted			$ 83.30
Price per share, Expired			8.70
Outstanding, Weighted-average exercise price, Beginning balance	$ 34.89	$ 30.77	28.22
Weighted-average exercise price, Granted			83.30
Weighted-average exercise price, Exercised	28.45	24.22	24.16
Weighted-average exercise price, Forfeited	44.58	28.24	43.74
Weighted-average exercise price, Expired			8.70
Outstanding, Weighted-average exercise price, Ending balance	35.24	34.89	30.77	$ 28.22
Weighted-average exercise price, Vested and exercisable	34.73	32.12	24.33
Weighted-average exercise price, Vested and expected to vest	$ 35.21	$ 34.75	$ 30.50
Remaining weighted-average contractual term, Outstanding	2 years 10 months 2 days	3 years 10 months 2 days	4 years 6 months 29 days	5 years 5 months 1 day
Remaining weighted-average contractual term, Vested and exercisable	2 years 9 months 21 days	3 years 9 months	4 years 4 months 20 days
Remaining weighted-average contractual term, Vested and expected to vest	2 years 10 months 2 days	3 years 10 months 2 days	4 years 6 months 29 days
Outstanding, Per share average intrinsic value	$ 34.07	$ 89.28	$ 88.31	$ 38.95
Per share average intrinsic value, Vested and exercisable	34.64	92.05	94.75
Per share average intrinsic value, Vested and expected to vest	34.11	89.42	88.58
Minimum
Class Of Stock [Line Items]
Outstanding, Price per share, Beginning balance	0.75	0.60	0.60
Price per share, Exercised	0.75	0.60	0.60
Price per share, Forfeited	38.54	24.52	24.52
Outstanding, Price per share, Ending balance	0.75	0.75	0.60	0.60
Price per share, Vested and exercisable	0.75	0.75	0.60
Price per share, Vested and expected to vest	0.75	0.75	0.60
Maximum
Class Of Stock [Line Items]
Outstanding, Price per share, Beginning balance	83.30	83.30	58.95
Price per share, Exercised	58.95	58.95	58.95
Price per share, Forfeited	58.95	44.19	58.95
Outstanding, Price per share, Ending balance	83.30	83.30	83.30	$ 58.95
Price per share, Vested and exercisable	83.30	83.30	83.30
Price per share, Vested and expected to vest	$ 83.30	$ 83.30	$ 83.30

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Restricted Stock Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Time based restricted stock units
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	58,589	42,028
Granted	87,902	31,877	42,028
Vested	(24,680)	(13,742)
Forfeited/canceled	(12,835)	(1,574)
Unvested restricted stock units/ awards outstanding, Ending balance	108,976	58,589	42,028
Performance and time based restricted stock units
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	8,739	13,109
Granted			13,109
Vested	(4,366)	(4,370)
Forfeited/canceled	(1,239)
Unvested restricted stock units/ awards outstanding, Ending balance	3,134	8,739	13,109
Restricted stock units
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	67,328	55,137
Granted	87,902	31,877	55,137
Vested	(29,046)	(18,112)
Forfeited/canceled	(14,074)	(1,574)
Unvested restricted stock units/ awards outstanding, Ending balance	112,110	67,328	55,137
Unvested and expected to vest restricted stock units/awards outstanding	103,087	62,504	48,589
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Beginning balance	$ 115.16	$ 90.05
Weighted-average grant date fair value per share, Granted	75.56	143.50	$ 90.05
Weighted-average grant date fair value per share, Vested	123.53	89.35
Weighted-average grant date fair value per share, Forfeited/canceled	102.89	106.55
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Ending balance	83.48	115.16	90.05
Weighted-average grant date fair value per share, Unvested and expected to vest restricted stock units/awards outstanding	$ 83.22	$ 115.98	$ 89.95
Time based restricted stock awards
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	36,937	20,789
Granted	54,853	22,645	20,789
Vested	(13,627)	(6,497)
Forfeited/canceled	(7,093)
Unvested restricted stock units/ awards outstanding, Ending balance	71,070	36,937	20,789
Performance and time based restricted stock awards
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	47,821	20,785
Granted	40,166	33,964	20,785
Vested	(15,732)	(6,928)
Forfeited/canceled	(9,627)
Unvested restricted stock units/ awards outstanding, Ending balance	62,628	47,821	20,785
Restricted stock awards
Class Of Stock [Line Items]
Unvested restricted stock units/ awards outstanding, Beginning balance	84,758	41,574
Granted	95,019	56,609	41,574
Vested	(29,359)	(13,425)
Forfeited/canceled	(16,720)
Unvested restricted stock units/ awards outstanding, Ending balance	133,698	84,758	41,574
Unvested and expected to vest restricted stock units/awards outstanding	79,473	65,773	34,051
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Beginning balance	$ 115.80	$ 91.52
Weighted-average grant date fair value per share, Granted	86.10	130.89	$ 91.52
Weighted-average grant date fair value per share, Vested	115.37	91.52
Weighted-average grant date fair value per share, Forfeited/canceled	109.11
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Ending balance	95.74	115.80	91.52
Weighted-average grant date fair value per share, Unvested and expected to vest restricted stock units/awards outstanding	$ 90.31	$ 115.85	$ 91.52

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Stock-based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock-based compensation expense by type of award:
Stock-based compensation expense	$ 9,129	$ 12,790	$ 9,640
Stock Option Plan Awards
Stock-based compensation expense by type of award:
Stock-based compensation expense	2,977	6,015	7,652
Restricted stock units and restricted stock awards
Stock-based compensation expense by type of award:
Stock-based compensation expense	5,413	5,890	1,447
Employee Stock Purchase Plan
Stock-based compensation expense by type of award:
Stock-based compensation expense	$ 739	$ 885	$ 541

Stockholders' Equity - Summar_4

Stockholders' Equity - Summary of Stock-based Compensation Expense Recognized in Income Statement (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class Of Stock [Line Items]
Stock-based compensation expense	$ 9,129	$ 12,790	$ 9,640
Cost of Revenue
Class Of Stock [Line Items]
Stock-based compensation expense	890	1,060	845
Research and Development
Class Of Stock [Line Items]
Stock-based compensation expense	1,100	1,314	1,015
Sales and Marketing
Class Of Stock [Line Items]
Stock-based compensation expense	1,755	2,355	1,558
General and Administrative
Class Of Stock [Line Items]
Stock-based compensation expense	$ 5,384	$ 8,061	$ 6,222

Stockholders' Equity - Assumpti

Stockholders' Equity - Assumptions Applied to Estimate Fair Value of Stock Option Awards (Details) - Stock options	12 Months Ended
	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk free interest rate, Minimum	1.65%
Risk free interest rate, Maximum	1.73%
Expected dividend yield	0.00%
Volatility, Minimum	41.61%
Volatility, Maximum	42.15%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	3 years 6 months 14 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	4 years

Stockholders' Equity - Assump_2

Stockholders' Equity - Assumptions Applied to Estimate Fair Value of Shares Issued Under ESPP (Details) - Employee Stock Purchase Plan	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	6 months	6 months	6 months
Risk free interest rate, Minimum	1.75%	1.63%	1.15%
Risk free interest rate, Maximum	2.53%	2.46%	1.63%
Expected dividend yield	0.00%	0.00%	0.00%
Volatility, Minimum	44.00%	37.34%	42.35%
Volatility, Maximum	47.00%	44.00%	45.34%

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	Dec. 31, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
Non-cancelable contractual obligations, 2020	$ 578
Non-cancelable contractual obligations, 2021	457
Non-cancelable contractual obligations, Total minimum payments	$ 1,035

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Details) $ in Thousands	1 Months Ended
	Oct. 31, 2019Lawsuit	Jan. 13, 2020Lawsuit	Dec. 31, 2019USD ($)	May 20, 2019Lawsuit
Commitments And Contingencies [Line Items]
Outstanding purchase orders with its outside vendors and suppliers | $			$ 54,500
Number of lawsuits				2
No. of additional shareholder derivative who filed lawsuits	3
Subsequent Event
Commitments And Contingencies [Line Items]
Number of derivative lawsuits		4

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Changes in Aggregate Product Warranty Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Product warranty liability at beginning of period	$ 9,530	$ 6,171	$ 3,480
Accruals for warranties issued	8,131	7,693	5,275
Adjustments related to preexisting warranties (including changes in estimates)	1,433	90	200
Settlements made (in cash or in kind)	(6,523)	(4,424)	(2,784)
Product warranty liability at end of period	$ 12,571	$ 9,530	$ 6,171

Foreign Currency Exchange Con_2

Foreign Currency Exchange Contracts and Hedging - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019USD ($)Contract	Dec. 31, 2018USD ($)Contract	Dec. 31, 2017USD ($)
Derivatives Fair Value [Line Items]
Number of contract designated hedges | Contract	11	29
Number of contract non-designated hedges | Contract	1	4
Non-Designated Derivative Contracts
Derivatives Fair Value [Line Items]
Derivative contracts notional amounts	$ 3,396,000	$ 2,336,000
Designated Derivative Contracts
Derivatives Fair Value [Line Items]
Derivative contracts notional amounts	35,708,000	21,374,000
Unrealized (loss) gain on derivative	$ (694,000)	$ 404,000	$ (121,000)
Minimum
Derivatives Fair Value [Line Items]
Derivative contracts expiration period	1 month
Maximum
Derivatives Fair Value [Line Items]
Derivative contracts expiration period	12 months

Quarterly Summary of Informat_3

Quarterly Summary of Information (Unaudited) - Summary of Unaudited Quarterly Statements of Income Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Total revenue	$ 78,917	$ 91,761	$ 101,063	$ 90,202	$ 86,531	$ 95,291	$ 97,238	$ 79,051	$ 361,943	$ 358,111	$ 249,438
Gross profit	33,922	43,315	50,215	44,409	43,570	48,813	48,470	37,727	171,861	178,580	121,237
Income (loss) before provision (benefit) for income taxes	(4,237)	8,753	13,684	6,072	5,823	11,299	13,646	9,687	24,272	40,455	29,656
Provision (benefit) for income taxes	(2,862)	1,890	3,524	770	(4,222)	(5,133)	(964)	(1,071)	3,322	(11,390)	8,654
Net income	$ (1,375)	$ 6,863	$ 10,160	$ 5,302	$ 10,045	$ 16,432	$ 14,610	$ 10,758	$ 20,950	$ 51,845	$ 21,002
Net income (loss) per share attributable to common stockholders:
Basic	$ (0.06)	$ 0.31	$ 0.47	$ 0.24	$ 0.47	$ 0.77	$ 0.69	$ 0.51	$ 0.96	$ 2.44	$ 1.02
Diluted	$ (0.06)	$ 0.31	$ 0.45	$ 0.24	$ 0.44	$ 0.73	$ 0.65	$ 0.48	$ 0.94	$ 2.30	$ 0.96
Weighted-average number of shares used in calculating net income per share attributable to common stockholders:
Basic common shares	21,878,004	21,840,473	21,815,634	21,750,305	21,544,202	21,324,256	21,172,170	21,026,154	21,821,104	21,266,696	20,683,807
Diluted common shares	21,878,004	22,191,688	22,359,679	22,534,885	22,600,038	22,659,052	22,503,749	22,295,213	22,241,064	22,514,513	21,897,988

Schedule II_ Valuation and Qu_2

Schedule II: Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 693	$ 1,415	$ 1,869
Additions	612	1,685	3,864
Deletions	1,100	2,677	4,418
Adjustments		270	100
Balance at End of Year	205	693	1,415
Allowance for Sales Returns
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	890	904	585
Additions	17,036	15,834	9,909
Deletions	16,763	15,848	9,590
Balance at End of Year	1,163	890	904
Allowance for Rental Revenue Adjustments
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	438	947	6,078
Additions	1,762	2,678	5,057
Deletions	1,789	2,917	10,088
Adjustments		(270)	(100)
Balance at End of Year	411	438	947
Allowance for Rental Asset Loss
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	594	754	725
Additions	188	408	561
Deletions	387	568	532
Balance at End of Year	$ 395	$ 594	$ 754