Vocera Communications (VCRA) 10-K 26 Feb 20 2019 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Feb. 24, 2020	Jun. 30, 2019
Entity Listings [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-35469
Entity Registrant Name	VOCERA COMMUNICATIONS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-3354663
Entity Address, Address Line One	525 Race Street
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95126
City Area Code	408
Local Phone Number	882-5100
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 811
Entity Common Stock, Shares Outstanding		31,761,283
Entity Central Index Key	0001129260
Document Period End Date	Dec. 31, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
NEW YORK STOCK EXCHANGE, INC.
Entity Listings [Line Items]
Title of 12(b) Security	Common Stock, $0.0003 par value
Trading Symbol	VCRA
Security Exchange Name	NYSE

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 25,704	$ 34,276
Short-term investments	204,164	186,894
Accounts receivable, net	42,547	40,127
Other receivables	6,312	4,148
Inventories	4,576	4,350
Prepaid expenses and other current assets	5,149	4,691
Total current assets	288,452	274,486
Property and equipment, net	8,661	7,468
Intangible assets, net	5,461	9,070
Goodwill	49,246	49,246
Deferred commissions	10,477	10,303
Other long-term assets	8,158	1,525
Total assets	370,455	352,098
Current liabilities
Accounts payable	6,036	4,217
Accrued payroll and other current liabilities	14,757	12,885
Deferred revenue, current	50,033	44,053
Total current liabilities	70,826	61,155
Deferred revenue, long-term	11,442	14,579
Other long-term liabilities	7,184	2,957
Total liabilities	206,630	189,231
Commitments and contingencies (Note 9)
Stockholders' equity
Preferred stock, $0.0003 par value - 5,000,000 shares authorized as of December 31, 2019 and December 31, 2018; zero shares issued and outstanding	0	0
Common stock, $0.0003 par value - 100,000,000 shares authorized as of December 31, 2019 and December 31, 2018; 31,660,709 and 30,708,138 shares issued and outstanding as of December 31, 2019 and December 31, 2018, respectively	9	9
Additional paid-in capital	313,963	295,647
Accumulated other comprehensive income (loss)	179	(443)
Accumulated deficit	(150,326)	(132,346)
Total stockholders’ equity	163,825	162,867
Total liabilities and stockholders’ equity	370,455	352,098
Convertible Debt, Noncurrent	$ 117,178	$ 110,540

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Paranthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Common stock, par value	$ 0.0003	$ 0.0003
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	31,660,709	30,708,138
Common stock, shares outstanding	31,660,709	30,708,138
Preferred Stock
Liabilities, Convertible Preferred Stock and Stockholders' Deficit
Preferred stock, par value	$ 0.0003	$ 0.0003
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue
Total revenue	$ 180,501	$ 179,630	$ 165,989
Cost of Revenue [Abstract]
Total cost of revenue	71,402	67,743	64,927
Gross profit	109,099	111,887	101,062
Operating expenses
Research and development	34,280	30,879	27,685
Sales and marketing	63,168	62,214	60,107
General and administrative	25,774	25,099	23,970
Total operating expenses	123,222	118,192	111,762
Loss from operations	(14,123)	(6,305)	(10,700)
Interest income	5,110	3,044	604
Interest Expense	8,789	5,241	0
Other expense, net	(158)	(1,523)	(42)
Loss before income taxes	(17,960)	(10,025)	(10,138)
Benefit from (provision for) income taxes	(20)	351	(759)
Net loss	$ (17,980)	$ (9,674)	$ (10,897)
Net loss per share:
Basic and diluted	$ (0.57)	$ (0.32)	$ (0.38)
Weighted average shares used to compute net loss per share:
Basic	31,273	30,041	28,655
Diluted	31,273	30,041	28,655
Product
Revenue
Total revenue	$ 92,561	$ 97,447	$ 91,585
Cost of Revenue [Abstract]
Total cost of revenue	29,039	27,425	27,244
Service
Revenue
Total revenue	87,940	82,183	74,404
Cost of Revenue [Abstract]
Total cost of revenue	$ 42,363	$ 40,318	$ 37,683
As Reported
Net loss per share:
Basic and diluted	$ (0.57)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net loss	$ (17,980)	$ (9,674)	$ (10,897)
Other comprehensive loss, net:
Change in unrealized gain (loss) on investments, net of tax	622	(252)	(122)
Comprehensive loss	$ (17,358)	$ (9,926)	$ (11,019)

Statements of Stockholders' Equ

Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive gain	Accumulated deficit	Restricted stock units	Restricted stock unitsCommon stock	Restricted stock unitsAdditional paid-in capital	Convertible DebtConvertible Senior Notes At 1.50%, Option Portion
Balance (shares) at Dec. 31, 2016		27,568,103
Balance at Dec. 31, 2016	$ 119,146	$ 8	$ 230,605	$ (69)	$ (111,398)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in a public offering		$ 1
Exercise of stock options (shares)		1,085,041
Exercise of stock options	7,917		7,916
Vested, Number of Shares							599,440
RSUs released net of shares withheld for tax settlement						$ (8,990)		$ (8,990)
ESPP, Shares Purchased for Award		159,532
Stock Issued During Period, Value, Employee Stock Purchase Plan	2,750		2,750
Effect of change in accounting principle related to stock-based compensation	0		377		(377)
Employee stock-based compensation expense	18,196		18,196
Net loss	(10,897)				(10,897)
Other comprehensive income	(122)			(122)
Balance (shares) at Dec. 31, 2017		29,412,116
Balance at Dec. 31, 2017	128,000	$ 9	250,854	(191)	(122,672)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in a public offering		$ 0
Exercise of stock options (shares)		531,788
Exercise of stock options	7,334		7,334
RSUs released net of shares withheld for tax settlement	$ (10,082)							(10,082)
ESPP, Shares Purchased for Award	157,426	157,426
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 3,270		3,270
Issuance of restricted stock awards							606,808
Employee stock-based compensation expense	20,964		20,964
Net loss	(9,674)				(9,674)
Other comprehensive income	(252)			(252)
Balance (shares) at Dec. 31, 2018		30,708,138
Balance at Dec. 31, 2018	162,867	$ 9	295,647	(443)	(132,346)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Carrying amount of equity component, net of capped calls									$ 23,307
Equity component of convertible senior notes, net					0
Exercise of stock options (shares)		187,174
Exercise of stock options	2,439		2,439
Vested, Number of Shares						978,785
RSUs released net of shares withheld for tax settlement	$ (11,460)							$ (11,460)
ESPP, Shares Purchased for Award	155,373	155,373
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 3,472		3,472
Issuance of restricted stock awards							610,024
Employee stock-based compensation expense	23,865		23,865
Net loss	(17,980)				(17,980)
Other comprehensive income	622
Balance (shares) at Dec. 31, 2019		31,660,709
Balance at Dec. 31, 2019	163,825	$ 9	$ 313,963	$ 179	$ (150,326)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	$ 622
Carrying amount of equity component, net of capped calls									$ 23,307

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net loss	$ (17,980)	$ (9,674)	$ (10,897)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	7,289	7,662	7,643
Inventory provision	67	362	380
Change in lease-related performance obligations	(1,173)	(998)	(864)
Share-based Compensation	23,865	20,964	18,196
Amortization of Debt Issuance Costs and Discounts	6,638	3,899	0
Other Operating Activities, Cash Flow Statement	1,016	22	26
Changes in assets and liabilities
Accounts receivable	(2,420)	(5,017)	(10,963)
Other receivables	(2,064)	(2,810)	(120)
Inventories	(293)	(1,898)	1,361
Prepaid expenses and other assets	(880)	(592)	(866)
Deferred commissions	(174)	(2)	121
Accounts payable	1,475	1,527	(611)
Increase (Decrease) in Other Accrued Liabilities	(2,431)	(2,629)
Increase (Decrease) in Other Operating Liabilities			(1,104)
Deferred revenue	2,843	3,482	5,434
Net cash provided by operating activities	15,778	14,298	7,736
Cash flows from investing activities
Payment for purchase of property and equipment	(4,576)	(4,892)	(2,834)
Purchase of short-term investments	(137,508)	(206,824)	(67,426)
Maturities of short-term investments	121,548	72,183	53,831
Net cash used in investing activities	(20,536)	(139,533)	(16,429)
Cash flows from financing activities
Proceeds from issuance of convertible senior notes, net of issuance costs	0	138,854	0
Cash from lease-related performance obligations	1,735	340	693
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Excluding Stock Options	3,472	3,269	2,750
Proceeds from exercise of stock options	2,440	7,327	7,917
RSUs released and tax settlement	(11,461)	(10,098)	(8,974)
Net cash provided by (used in) financing activities	(3,814)	130,785	2,386
Net increase (decrease) in cash and cash equivalents	(8,572)	5,550	(6,307)
Cash and cash equivalents at beginning of period	34,276	28,726	35,033
Cash and cash equivalents at end of period	25,704	34,276	28,726
Supplemental cash flow information
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	2,156	1,066	0
Cash paid for income taxes	345	216	342
Supplemental disclosure of non-cash investing and financing activities
Property and equipment in accounts payable and accrued liabilities	458	114	102
Payment for purchase of capped calls	$ 0	$ (8,907)	$ 0

Convertible Senior Notes

Convertible Senior Notes	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Convertible Senior Notes	8. Convertible Senior Notes In May 2018, the Company issued $143.75 million aggregate principal amount of 1.50% Convertible Senior Notes due 2023, including $18.75 million aggregate principal amount of such notes pursuant to the exercise in full of options granted to the initial purchasers, collectively the “Notes.” The Notes are unsecured, unsubordinated obligations and bear interest at a fixed rate of 1.50% per annum, payable semi-annually in arrears on May 15 and November 15 of each year, commencing on November 15, 2018. The total net proceeds from the offering, after deducting initial purchase discounts and estimated debt issuance costs, were approximately $138.9 million . Each $1,000 principal amount of the Notes will initially be convertible into 31.0073 shares of the Company’s common stock, the “Conversion Option,” which is equivalent to an initial conversion price of approximately $32.25 per share, subject to adjustment upon the occurrence of specified events. The Notes will be convertible at the option of the holders at any time prior to the close of business on the business day immediately preceding February 15, 2023, only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on June 30, 2018 (and only during such calendar quarter), if the last reported sale price of the Company common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price of the Notes on each applicable trading day; (2) during the five business day period after any ten consecutive trading day period in which the trading price per $1,000 principal amount of the Notes for each day of that ten day consecutive trading day period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate of the Notes on such trading day; or (3) upon the occurrence of specified corporate events (as set forth in the indenture governing the Notes). On or after February 15, 2023 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their Notes at any time, regardless of the foregoing circumstances. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock, at the Company’s election. If certain specified fundamental changes occur (as set forth in the indenture governing the Notes) prior to the maturity date, holders of the Notes may require the Company to repurchase for cash all or any portion of their Notes at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. In addition, if specific corporate events occur prior to the applicable maturity date, the Company will increase the conversion rate for a holder who elects to convert their notes in connection with such a corporate event in certain circumstances. It is the Company’s current intent and policy to settle conversions through combination settlement which involves repayment of the principal portion in cash and any excess of the conversion value over the principal amount in shares of its common stock. During the year ended December 31, 2019, the conditions allowing holders of the Notes to convert have not been met. The Notes are therefore not convertible during the year ended December 31, 2019 and are classified as long-term debt. In accounting for the transaction, the Notes were separated into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar debt instrument that does not have an associated convertible feature. The carrying amount of the equity component representing the Conversion Option was $33.4 million and was determined by deducting the fair value of the liability component from the par value of the Notes. The equity component was recorded in additional paid-in capital and will be remeasured as long as it continues to meet the conditions for equity classification. The excess of the principal amount of the liability component over its carrying amount, the “debt discount,” is amortized to interest expense over the contractual term of the Notes at an effective interest rate of 7.6% . In accounting for the debt issuance costs of $4.9 million related to the Notes, the Company allocated the total amount incurred to the liability and equity components of the Notes based on their relative values. Issuance costs attributable to the liability component were $3.8 million and will be amortized to interest expense using the effective interest method over the contractual term of the Notes. Issuance costs attributable to the equity component were $1.1 million and are included with the equity component in additional paid-in capital. The Notes consist of the following: (in thousands) December 31, December 31, Liability: Principal $ 143,750 $ 143,750 Unamortized debt discount (23,880 ) (29,846 ) Unamortized issuance costs (2,692 ) (3,364 ) Net carrying amount $ 117,178 $ 110,540 Stockholders’ equity: Debt discount for conversion option $ 33,350 $ 33,350 Issuance costs $ (1,136 ) $ (1,136 ) Net carrying amount $ 32,214 $ 32,214 The total estimated fair value of the Notes as of December 31, 2019 was approximately $142.4 million . The fair value was determined based on the closing trading price per $100 of the Notes as of the last day of trading for the period. The fair value of the Notes is primarily affected by the trading price of the Company’s common stock and market interest rates. Based on the closing price of the Company’s common stock of $20.76 on December 31, 2019, the if-converted value of the Notes of $92.5 million was less than their principal amount. Interest expense related to the Notes is as follows: Year ended December 31, (in thousands) 2019 2018 Contractual interest expense $ 2,150 $ 1,342 Amortization of debt discount 5,966 3,504 Amortization of issuance costs 673 395 Total interest expense $ 8,789 $ 5,241 Capped Calls In connection with the pricing of the Notes, the Company entered into privately negotiated capped call transactions with certain counterparties, the “Capped Calls.” The Capped Calls each have an initial strike price of approximately $32.25 per share, subject to certain adjustments, which correspond to the initial conversion price of the Notes. The Capped Calls have initial cap prices of $38.94 per share, subject to certain adjustments. The Capped Calls cover, subject to anti-dilution adjustments, approximately 4.5 million shares of the Company’s common stock. Conditions that cause adjustments to the initial strike price of the Capped Calls mirror conditions that result in corresponding adjustments for the Notes. The Capped Calls are generally intended to reduce or offset the potential dilution to the Company’s common stock upon any conversion of the Notes with such reduction or offset, as the case may be, subject to a cap based on the cap price. For accounting purposes, the Capped Calls are separate transactions, and not part of the terms of the Notes. As these transactions meet certain accounting criteria, the Capped Calls are recorded in stockholders' equity and are not accounted for as derivatives. The cost of $8.9 million incurred in connection with the Capped Calls was recorded as a reduction to additional paid-in capital. The net impact to the Company’s stockholders' equity, included in additional paid-in capital, of the above components of the Notes is as follows: (in thousands) December 31, Conversion option $ 33,350 Purchase of capped calls $ (8,907 ) Issuance costs $ (1,136 ) Total $ 23,307 Impact on Earnings Per Share The Notes will not have an impact on the Company’s diluted earnings per share until they meet the criteria for conversion, as discussed above, as the Company intends to settle the principal amount of the Notes in cash upon conversion. Under the treasury stock method, in periods when the Company reports net income, the Company is required to include the effect of additional shares that may be issued under the Notes when the price of its’ common stock exceeds the conversion price. However, upon conversion, there will be no economic dilution from the Notes until the average market price of the Company’s common stock exceeds the cap price of $38.94 per share, as exercise of the capped calls offsets any dilution from the Notes from the conversion price up to the cap price. Capped Calls are excluded from the calculation of diluted earnings per share, as they would be anti-dilutive under the treasury stock method.

Revenue, deferred revenue, and

Revenue, deferred revenue, and deferred commissions	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue, deferred revenue, and deferred commissions	2. Revenue, deferred revenue and deferred commissions Disaggregation of Revenue A typical sales arrangement involves multiple arrangements, such as sales of the Company’s proprietary communication device ("Vocera Badge"), perpetual software licenses, professional services, and maintenance and support services which entitle customers to unspecified upgrades, patch releases and telephone-based support. The following table depicts the disaggregation of revenue according to revenue type and is consistent with how the Company evaluates its financial performance: Years ended December 31, (in thousands) 2019 2018 2017 Revenue Product Device $ 61,224 $ 60,130 $ 61,746 Software 31,337 37,317 29,839 Total product 92,561 97,447 91,585 Service Maintenance and support 68,846 62,267 52,342 Professional services and training 19,094 19,916 22,062 Total service 87,940 82,183 74,404 Total revenue $ 180,501 $ 179,630 $ 165,989 Costs to obtain and fulfill a contract The Company capitalizes certain incremental contract acquisition costs consisting primarily of commissions paid and the related payroll taxes when customer contracts are signed. The Company determines whether costs should be deferred based on its sales compensation plans, if the commissions are incremental and would not have been incurred absent the execution of the customer contract. Sales commissions for renewals of customer contracts are not commensurate with the commissions paid for the acquisition of the initial contract given the substantive difference in commission rates in proportion to their respective contract values. Commissions paid upon the initial acquisition of a contract are amortized over the estimated period of benefit, which may exceed the term of the initial contract. Accordingly, amortization of deferred costs is recognized on a systematic basis that is consistent with the pattern of revenue recognition allocated to each performance obligation and is included in sales and marketing expense in the consolidated statements of operations. The Company determines its estimated period of benefit, up to five years, by evaluating the expected renewals of its customer contracts, the duration of its relationships with its customers and other factors. Deferred costs are periodically reviewed for impairment. Changes in the balance of total deferred commissions (contract asset) during the year ended December 31, 2019 and 2018 are as follows: (in thousands) December 31, 2018 Additions Commissions Recognized December 31, 2019 Deferred commissions $ 10,303 $ 7,761 $ (7,587 ) $ 10,477 (in thousands) December 31, 2017 Additions Commissions Recognized December 31, 2018 Deferred commissions $ 10,301 $ 8,327 $ (8,325 ) $ 10,303 Of the $10.5 million total deferred commissions balance as of December 31, 2019, the Company expects to recognize approximately 49.0% as commission expense over the next 12 months and the remainder thereafter. Deferred revenue The Company records deferred revenue when cash payments are received in advance of the performance under the contract. The current portion of deferred revenue represents the amounts that are expected to be recognized as revenue within one year of the consolidated balance sheet date. Changes in the balance of total deferred revenue (contract liability) during the years ended December 31, 2019 and 2018 are as follows: (in thousands) December 31, 2018 Additions Revenue Recognized December 31, 2019 Deferred revenue $ 58,632 $ 82,042 $ (79,199 ) $ 61,475 (in thousands) December 31, 2017 Additions Revenue Recognized December 31, 2018 Deferred revenue $ 55,151 $ 77,969 $ (74,488 ) $ 58,632 Revenue recognized during the year ended December 31, 2019 from deferred revenue balances as of December 31, 2018 was $48.6 million . Revenue recognized during the year ended December 31, 2018 from deferred revenue balances as of December 31, 2017 was $42.6 million . The “contracted but not recognized” performance obligations represent the Company’s deferred revenue and non-cancelable backlog amounts. This balance as of December 31, 2019 was $123.5 million , of which the Company expects to recognize approximately 66% of the revenue over the next 12 months and the remainder thereafter.

The Company and Summary of Sign

The Company and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
The Company and Summary of Significant Accounting Policies	The Company and Summary of Significant Accounting Policies Background Vocera Communications, Inc. and its subsidiaries (collectively, the Company) is a provider of secure, integrated, intelligent communication and clinical workflow solutions, focused on empowering mobile workers in healthcare, hospitality, retail, energy, education and other mission-critical mobile work environments, in the United States and internationally. The significant majority of the Company's business is generated from sales of its solutions in the healthcare market to help its customers improve quality of care, safety, patient and staff experience and increase operational efficiency. The Vocera communication and collaboration solution includes: an intelligent enterprise software platform; a lightweight, wearable, voice-controlled communication badge and newly introduced Smartbadge; and smartphone applications. The solution enables users to connect instantly with other staff simply by saying the name, function or group name of the desired recipient. It also delivers HIPAA-compliant secure text messages, alerts and alarms directly to a range of smartphones or the Smartbadge both inside and outside the hospital, replacing legacy pagers and in-building wireless phones. The Company was incorporated in Delaware on February 16, 2000. The Company formed wholly-owned subsidiaries Vocera Communications UK Ltd and Vocera Communications Australia Pty Ltd. in 2005, Vocera Canada, Ltd. in 2010, Vocera Communications India Private Ltd. in 2013, Vocera Communications Middle East FZ LLC in 2014 and acquired Extension, LLC in 2016. Since its inception, the Company has incurred significant losses and, as of December 31, 2019 , had an accumulated deficit of $150.3 million . The Company has funded its operations primarily with customer payments for its products and services, proceeds from the issuance of common stock in connection with its initial public offering (IPO) and follow-on offering and proceeds from the issuance of convertible senior notes. As of December 31, 2019 , the Company had cash, cash equivalents and short-term investments of $229.9 million . The Company believes that its existing sources of liquidity will satisfy its working capital and capital requirements for at least the next twelve months. Basis of presentation The consolidated financial statements include the accounts of Vocera Communications, Inc. and its wholly owned subsidiaries. All inter-company transactions and balances have been eliminated in consolidation. The accompanying notes are prepared in accordance with accounting principles generally accepted in the United States (GAAP). Use of estimates and reclassifications The preparation of financial statements in conformity with GAAP requires the Company 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 financial statements and the reported amounts of revenue and expense during the reporting periods. The estimates include, but are not limited to, revenue recognition, warranty reserves, inventory reserves, bonuses, goodwill and intangible assets, stock-based compensation expense, provisions for income taxes and contingencies. Actual results could differ from these estimates, and such differences could be material to the Company’s financial position and results of operations. Cash, cash equivalents and short-term investments The Company’s cash equivalents and short-term investments consist of money market funds, commercial paper, U.S. government agency notes, U.S. Treasury notes and corporate debt. These investments are classified as available-for-sale securities and are carried at fair value with the unrealized gains and losses reported as a component of stockholders’ equity. Management determines the appropriate classification of its investments at the time of purchase and re-evaluates the available-for-sale designations as of each balance sheet date. Investments with an original purchase maturity of three months or less are classified as cash equivalents, all those with longer maturities are classified as short-term investments, which are available-for-sale. Allowance for doubtful accounts The allowance for doubtful accounts reflects the Company’s best estimate of probable losses inherent in the Company’s receivables portfolio determined on the basis of historical experience, specific allowances for known troubled accounts and other currently available evidence. The Company has not experienced significant credit losses from its accounts receivable. The Company performs a regular review of its customers’ payment histories and associated credit risks as it does not require collateral from its customers. No allowance for doubtful accounts was recorded in the years ended December 31, 2019, 2018 or 2017. Inventories Inventories are valued at the lower of standard cost (which approximates actual cost on a first-in, first-out basis) or market (net realizable value or replacement cost). The Company assesses the valuation of inventory and periodically writes down the value for estimated excess and obsolete inventory based upon assumptions about future demand and market conditions. Concentration of credit risk and other risks and uncertainties Financial instruments that subject the Company to concentration of credit risk consist primarily of cash, cash equivalents and short-term investments. The Company’s cash and cash equivalents are primarily deposited with high quality financial institutions and in money market funds. Deposits at these institutions and funds may, at times, exceed federally insured limits. Management believes that these financial institutions and funds are financially sound and, accordingly, that minimal credit risk exists. The Company has not experienced any losses on its deposits of cash and cash equivalents. Marketable securities are stated at fair value and accounted for as available-for-sale within short-term investments. The counterparties to the agreements relating to the Company’s investment securities consist of major corporations, financial institutions and government agencies of high credit standing. The primary hardware components of the Company’s products are currently manufactured by third-party contractors in Mexico and Taiwan. A significant disruption in the operations of these contractors may impact the production of the Company’s products for a substantial period of time, which could harm the Company’s business, financial condition and results of operations. Concentration of credit risk with respect to trade accounts receivable is considered to be limited due to the diversity of the Company’s customer base and geographic sales areas. At December 31, 2019 and 2018 , no customer accounted for 10% or more of accounts receivable. At December 31, 2019 and 2018, one reseller represented 19.3% and 26.4% , respectively of accounts receivable. For the years ended December 31, 2019 , 2018 and 2017 , no customer represented 10% or more of revenue. Property and equipment Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful economic lives of the assets. Assets generally have useful economic lives of three years except for leasehold improvements, which are amortized using the straight-line method over the shorter of the remaining lease term or the estimated useful life of the related assets. Purchased software also generally has a useful economic life of three years , except for major ERP implementations, for which the Company assumes a useful economic life of five years . Upon retirement or sale, the cost and related accumulated depreciation and amortization are removed from the consolidated balance sheet and the resulting gain or loss is reflected in operations. Maintenance and repairs which are not considered improvements and do not extend the useful life of the assets are charged to operations as incurred. The Company periodically reviews property and equipment for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset is impaired or the estimated useful lives are no longer appropriate. Fair value is estimated based on undiscounted future cash flows. If indicators of impairment exist and the undiscounted projected cash flows associated with such assets are less than the carrying amount of the asset, an impairment loss is recorded to write the asset down to its estimated fair values. To date, the Company has not recorded any impairment charges. Internal-use software development costs For internal-use software, the Company capitalizes certain internal and external costs incurred in its acquisition and creation. Capitalized internal-use software is included in property and equipment amortized on a straight-line basis over the estimated useful life of the related asset, generally three years . Based on the authoritative guidance, costs incurred either before or after the period satisfying the capitalization criteria, together with costs incurred for training and maintenance, are expensed as incurred. For the years ended December 31, 2019 , 2018 and 2017 , the Company capitalized costs of $0.6 million , $0.7 million and $0.3 million , respectively. Goodwill and intangible assets The Company allocates the purchase price of any acquisitions to tangible assets and liabilities and identifiable intangible assets acquired. Any residual purchase price is recorded as goodwill. Goodwill Goodwill is tested for impairment at the reporting unit level at least annually, or more often if events or changes in circumstances indicate the carrying value may not be recoverable. The Company has identified two operating segments (Product and Service) which management also considers to be reporting units. In testing for goodwill impairment, the Company may elect to utilize a qualitative assessment to evaluate whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If such qualitative assessment indicates that goodwill impairment is more likely than not, the Company performs a two- step impairment test. The Company performed its goodwill impairment assessment on October 1, 2019 using a qualitative assessment and determined that no impairment existed as of the date of the impairment test because the fair value of each reporting unit more likely than not exceeded its carrying value. As of December 31, 2019 , no changes in circumstances indicate that goodwill carrying values may not be recoverable. Intangible assets Intangible assets are amortized over their estimated useful lives. Upon completion of development, acquired in-process research and development assets are generally considered amortizable, finite-lived assets and are amortized over their estimated useful lives. Finite-lived intangible assets consist of customer relationships, developed technology, trademarks, backlog and non-compete agreements. The Company evaluates intangible assets for impairment by assessing the recoverability of these assets whenever adverse events or changes in circumstances or business climate indicate that expected undiscounted future cash flows related to such intangible assets may not be sufficient to support the net book value of such assets. An impairment is recognized in the period of identification to the extent the carrying amount of an asset exceeds the fair value of such asset. No impairment of intangible assets was recorded in the years ended December 31, 2019 , 2018 or 2017 . Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in other long-term assets, accrued payroll and other current liabilities and other long-term liabilities on the consolidated balance sheets. Sales-type leases are included in other receivables, accrued payroll and other current liabilities and other long-term liabilities on the consolidated balance sheets. The Company has elected an accounting policy to not recognize short-term leases (one year or less) on the consolidated balance sheet. The Company also elected the package of practical expedients which applies to leases that commenced before the adoption date. By electing the package of practical expedients, the Company did not need to reassess whether any existing contracts are or contained a lease or the lease classification for any existing leases. Operating lease right-of-use assets and operating lease liabilities are recognized based on the present value of the lease payments over the lease term at commencement date. As most of the Company’s leases do not provide an implicit rate, the incremental borrowing rate is used based on the information available at commencement date in determining the present value of future payments. For those leases that existed as of January 1, 2019, we used our incremental borrowing rate based on information available at that date. We apply a portfolio approach for determining the incremental borrowing rate based on the applicable lease terms and the current economic environment and we utilize available information regarding our borrowing rates. The operating lease right-of-use asset also includes any lease payments made 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 minimum lease payments is recognized on a straight-line basis over the lease term. The Company accounts for lease components and nonlease components as a single lease component. Revenue recognition The core principle of ASC 606 is to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This principle is achieved through applying the following five-step approach: • Identification of the contract, or contracts, with a customer - A contract with a customer exists when (i) the Company enters into an enforceable contract with a customer that defines each party’s rights regarding the goods or services to be transferred and identifies the payment terms related to these goods or services, (ii) the contract has commercial substance and, (iii) the Company determines that collection of substantially all consideration for goods or services that are transferred is probable based on the customer’s intent and ability to pay the promised consideration. The Company applies judgment in determining the customer’s ability and intention to pay, which is based on a variety of factors including the customer’s historical payment experience or, in the case of a new customer, published credit and financial information pertaining to the customer. Customer payments received by the Company are non-refundable. • Identification of the performance obligations in the contract - Performance obligations promised in a contract are identified based on the goods or services that will be transferred to the customer that are capable of being both: a) functionally distinct, whereby the customer can benefit from the goods or service either on their own or together with other resources that are readily available from third parties or from the Company, and b) contractually distinct, whereby the transfer of the goods or services is separately identifiable from other promises in the contract. To the extent a contract includes multiple promised goods or services, the Company applies judgment to determine whether promised goods or services are capable of being distinct and distinct in the context of the contract. If these criteria are not met the promised goods or services are accounted for as a combined performance obligation. • Determination of the transaction price - The transaction price is determined based on the consideration to which the Company will be entitled in exchange for transferring goods or services to the customer. • Allocation of the transaction price to the performance obligations in the contract - If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation based on a relative standalone selling price, (SSP) basis. The Company determines standalone selling price based on the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price taking into account available information such as market conditions and internally approved pricing guidelines related to the performance obligations. • Recognition of revenue when, or as, the Company satisfies a performance obligation - The Company satisfies performance obligations either over time or at a point in time as discussed in further detail below. Revenue is recognized at the time the related performance obligation is satisfied by transferring a promised good or service to a customer. Device revenue - In transactions where the Company delivers hardware, the Company considers itself to be the principal in the transaction and records revenue and costs of goods sold on a gross basis. Hardware revenue is generally recognized upon transfer of control to the customer. Software revenue - Revenue from the Company’s software products is generally recognized upon transfer of control to the customer. Additional software revenue is derived from the sale of term licenses and cloud-based subscriptions, which can be renewed on a subscription basis. Revenue is generally recognized upon shipment of hardware and perpetual licenses and, in the case of subscription software, ratably over the applicable term. Maintenance and support revenue - The Company generates maintenance and support revenue primarily from post contract support (PCS) contracts, and, to a lesser extent, from sales of extended warranties on the Vocera Badge. The majority of software sales are in conjunction with PCS contracts, which generally have one-year terms. The Company recognizes revenue from PCS contracts ratably over the contractual service period. The service period typically commences upon transfer of control of the corresponding software products to the customer. The Company recognizes revenue from extended warranty contracts ratably over their contractual service period, which is primarily two years . This period starts one year from the date on which the transfer of control on the underlying hardware occurs because the hardware generally carries a one-year warranty. Professional services and training revenue - Professional services and training revenue is generated when the Company installs and configures its software and devices at new or existing customer sites. The Company recognizes revenue related to professional services as they are performed. Contracts with multiple performance obligations - Some of the Company’s contracts with customers contain multiple performance obligations. For these contracts, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to the separate performance obligations on a relative stand-alone selling price basis. For deliverables that are routinely sold separately, such as maintenance and support on the core offerings, the Company determines SSP by evaluating renewals over the trailing 12-months. For those that are not sold routinely, the Company determines SSP based on its overall pricing trends and objectives, taking into consideration market conditions and other factors, including the value of the contracts and the products sold. Contract balances - The timing of revenue recognition may differ from the timing of invoicing to customers. Accounts receivable are recorded at the invoiced amount and in the period the Company delivers goods or provides services or when the Company’s right to consideration is unconditional. Payment terms on invoiced amounts are typically 30 days . The balance of accounts receivable, net of allowance for doubtful accounts, as of December 31, 2019 and 2018 is presented in the accompanying consolidated balance sheets. In situations where revenue recognition occurs before invoicing, an unbilled receivable is created, which represents a contract asset. As of December 31, 2019 and 2018 contract assets totaling $4.3 million and $2.4 million , respectively, were included in other receivables in the consolidated balance sheet. Revenue from sales-type leases A portion of the Company's sales are made through multi-year lease agreements with customers. When these arrangements are considered sales-type leases, upon delivery of leased products to customers, the Company recognizes revenue for such products in an amount equal to the net present value of the minimum lease payments. Unearned income is recognized as part of product revenue under the effective interest method. The Company recognizes revenue related to certain executory costs, including maintenance and extended warranty, ratably over the term of the underlying arrangements. The Company recognizes revenue related to battery refresh executory costs when such executory costs are incurred. Proceeds from transfers of sales-type leases to third-party financial companies are allocated between the net investment in sales-type leases and the executory cost component for remaining service obligations based on relative present value. The difference between the amount of proceeds allocated to the net investment in lease and the carrying value of the net investment in lease is included in product revenue. Proceeds allocated to the executory cost component are accounted for as financing liabilities. For the year ended December 31, 2019 , the Company transferred $3.5 million of lease receivables, recording a net loss of $0.3 million and $1.7 million of new financing liabilities for future performance of executory service obligations. For the year ended December 31, 2018 , the Company transferred $0.4 million of lease receivables, recording an immaterial net loss and $0.3 million of new financing liabilities for future performance of executory service obligations. For lease receivables retained as of December 31, 2019 and 2018 , the Company recorded $0.9 million and $0.7 million , respectively, of net investment in sales-type leases, equivalent to the minimum lease payments for the delivered product. Shipping and handling costs Shipping and handling costs charged to customers are included in revenue and the associated expense is recorded in cost of revenue in the consolidated statements of operations for all periods presented. Research and development expenditures Research and development costs are charged to operations as incurred. Software development costs incurred for external products prior to the establishment of technological feasibility are included in research and development and are expensed as incurred. After technological feasibility is established, material software development costs up to general availability of the software will be capitalized and amortized on a straight-line basis over the estimated product life, or based on the ratio of current revenues to total projected product revenue, whichever is greater. To date, the time between the establishment of technological feasibility and general availability has been very short and therefore no significant costs have been incurred. Accordingly, the Company has not capitalized any software development costs related to research and development expenditures. Advertising costs Advertising costs are included in sales and marketing expense and are expensed as incurred. Advertising costs for the years ended December 31, 2019 , 2018 and 2017 were immaterial. Product warranties The Company offers warranties on certain products and records a liability for the estimated future costs associated with warranty claims, which is based upon historical experience and the Company’s estimate of the level of future costs. The Company provides for the estimated costs of hardware warranties at the time the related revenue is recognized. Costs are estimated based on historical and projected product failure rates, historical and projected repair costs, and knowledge of specific product failures (if any). The specific hardware warranty includes parts and labor over a period generally ranging from one to three years. The Company provides no warranty for software. The Company regularly re-evaluates its estimates to assess the adequacy of the recorded warranty liabilities and adjust the amounts as necessary. Warranty costs are reflected in the consolidated statement of operations as cost of revenue. Stock-based compensation Stock-based compensation is measured at grant date based on the fair value of the award using the grant date closing stock price and is expensed on a straight-line basis over the requisite service period. Income taxes The Company uses the asset and liability method of accounting for income taxes. Under this method, the Company records deferred income taxes based on temporary differences between the financial reporting and tax bases of assets and liabilities and use enacted tax rates and laws that the Company expects will be in effect when they recover those assets or settle those liabilities, as the case may be, to measure those taxes. In cases where the expiration date of tax carryforwards or the projected operating results indicate that realization is not likely, the Company provides for a valuation allowance. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company has deferred tax assets, resulting from net operating losses, research and development credits and temporary differences that may reduce taxable income in future periods. A valuation allowance is required when it is more likely than not that all or a portion of a deferred tax asset will not be realized. In assessing the need for a valuation allowance, the Company estimates future taxable income, considering the feasibility of ongoing tax-planning strategies and the realizability of tax loss carryforwards. Valuation allowances related to deferred tax assets can be impacted by changes in tax laws, changes in statutory tax rates and future taxable income levels. If the Company were to determine that it would be able to realize its deferred tax assets in the future in excess of the net carrying amounts, it would decrease the recorded valuation allowance through an increase to income in the period in which that determination is made. Due to the history of losses the Company has generated in the past, the Company believes that it is not more likely than not that all of the deferred tax assets in the U.S. and Canada can be realized as of December 31, 2019 and 2018, respectively. Accordingly, the Company has recorded a full valuation allowance on its deferred tax assets for these years. At December 31, 2019 , the Company had a valuation allowance against net deferred tax assets of $40.4 million . There is inherent uncertainty in evaluating the sustainability of the income tax positions the Company takes on its tax returns. The Company assesses its income tax positions and records tax benefits for all years subject to examination based upon management’s evaluation of the facts, circumstances and information available at the reporting date. For those tax positions where it is more likely than not that a tax benefit will be sustained, the Company has recorded the highest amount of tax benefit with a greater than 50% likelihood of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. For those income tax positions where it is not more likely than not that a tax benefit will be realizable, no tax benefit has been recognized in the financial statements. The Company includes interest and penalties with income taxes in the accompanying statement of operations. All of the Company’s net operating losses and research credit carryforwards are subject to adjustment by tax authorities and all years after 2012 are still subject to tax authority examinations. The Company is currently not subject to any income tax audit examinations by tax authorities in any jurisdictions including U.S. federal, state and local or foreign countries. Foreign currency translation The functional currency of the Company’s foreign subsidiaries is the U.S. dollar. Accordingly, monetary assets and liabilities in non-functional currency of these subsidiaries are remeasured using exchange rates in effect at the end of the period. Revenues and costs in local currency are remeasured using average exchange rates for the period, except for costs related to those consolidated balance sheet items that are remeasured using historical exchange rates. The resulting remeasurement gains and losses are included in the Company’s consolidated statements of operations. Translation gains and losses have not been significant to date. Segments Operating segments are components of an enterprise for which separate financial information is available and is evaluated regularly by the Company’s chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker is the Chief Executive Officer. The Company has two operating segments which are both reportable business segments: (i) Product; and (ii) Service. Comprehensive loss For the years ended December 31, 2019 , 2018 and 2017, the only component of other comprehensive loss was unrealized (losses) gains on available-for-sale securities. Related party transactions During the years ended December 31, 2019 , 2018 and 2017 , the Company had revenue transactions with a related party, the University of Chicago Medical Center (UCMC), for $1.3 million , $0.4 million and $0.4 million , respectively, relating to consulting services and technology solutions. One of the Company's board members is the President of UCMC. Recently adopted accounting pronouncement In February 2016, the FASB amended lease accounting requirements to begin recording assets and liabilities arising from leases on the balance sheet. The new guidance requires significant additional disclosures about the amount, timing and uncertainty of cash flows from leases. We adopted this new guidance effective January 1, 2019 using a modified retrospective approach. The modified retrospective approach includes a number of optional practical expedients that entities may elect to apply. The Company elected the package of practical expedients permitted under the transition guidance within the new standard. The adoption of the standard resulted in recognition of right-of-use assets, which includes the impact of existing deferred rents and tenant improvement allowances of $5.1 million and lease liabilities of $6.7 million as of January 1, 2019. The standard did not affect our consolidated net earnings or cashflows. In February 2018, the FASB issued new guidance which allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act and required certain disclosures about stranded tax effects. We adopted this standard effective January 1, 2019 on a prospective basis. The adoption of this guidance did not have an impact on the Company’s consolidated financial statements. In August 2018, the SEC adopted the final rule under SEC Release No. 33-10532, Disclosure Update and Simplification, amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements on the analysis of stockholders' equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders' equity presented in the balance sheet must be provided in a note or separate statement. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of comprehensive income is required to be filed. This final rule was effective on November 5, 2018. The Company adopted this guidance in the first quarter of fiscal year 2019. The adoption of this guidance did not have an impact on the Company's consolidated financial statements. Recent accounting pronouncemen

Fair value of financial instrum

Fair value of financial instruments	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair value of financial instruments	air value of financial instruments The carrying values of the Company’s cash and cash equivalents and short-term investments approximate their fair value due to their short-term nature. As a basis for determining the fair value of its assets and liabilities, the Company utilizes a three-tier fair value hierarchy which prioritizes the inputs used in measuring fair value as follows: (Level 1) observable inputs such as quoted prices in active markets; (Level 2) inputs other than the quoted prices in active markets that are observable either directly or indirectly; and (Level 3) unobservable inputs in which there is little or no market data which requires the Company to develop its own assumptions. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. For the years ended December 31, 2019 , 2018 and 2017 , there have been no transfers between Level 1 and Level 2 fair value instruments and no transfers in or out of Level 3. The Company's money market funds are classified within Level 1 of the fair value hierarchy because they are valued using quoted market prices. The fair value of the Company's Level 2 fixed income securities are obtained from independent pricing services, which may use quoted market prices for identical or comparable instruments or model-driven valuations using observable market data or other inputs corroborated by observable market data. The Company does not have any financial instruments which are valued using Level 3 inputs. In addition to its cash, cash equivalents and short-term investments, the Company measures the fair value of its Convertible Senior Notes on a quarterly basis for disclosure purposes. The Company considers the fair value of the Convertible Senior Notes at December 31, 2019 to be a Level 2 measurement due to limited trading activity of the Convertible Senior Notes. Refer to Note 8 to the consolidated financial statements for further information. The table below summarizes the Company’s assets that are measured at fair value on a recurring basis, by level, within the fair value hierarchy as of December 31, 2019 and 2018 , respectively. December 31, 2019 December 31, 2018 (in thousands) Level 1 Level 2 Total Level 1 Level 2 Total Assets Money market funds $ 4,086 $ — $ 4,086 $ 3,737 $ — $ 3,737 Commercial paper — 12,854 12,854 — 16,570 16,570 U.S. government agency securities — 3,000 3,000 — 3,325 3,325 Corporate debt securities — 188,310 188,310 — 166,759 166,759 Total assets measured at fair value $ 4,086 $ 204,164 $ 208,250 $ 3,737 $ 189,384 $ 193,121 The financial accounts that are not subject to recurring fair value measurement include trade and other receivables, prepaid expenses and other current assets, total current liabilities and deferred revenues, both current and long-term. Due to their short maturities, the carrying amounts of these accounts approximate their fair values.

Cash, Cash Equivalents and Shor

Cash, Cash Equivalents and Short-term Investments	12 Months Ended
	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Short-term Investments	Cash, Cash Equivalents and Short-Term Investments The following tables display gross unrealized gains and losses for cash, cash equivalents and available-for-sale investments for the periods presented: December 31, 2019 (in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair value Cash and cash equivalents: Demand deposits and other cash $ 21,618 $ — $ — $ 21,618 Money market funds 4,086 — — 4,086 Total cash and cash equivalents 25,704 — — 25,704 Short-Term Investments: Commercial paper 12,861 — (7 ) 12,854 U.S. government agency securities 3,000 — — 3,000 Corporate debt securities 187,866 499 (55 ) 188,310 Total short-term investments 203,727 499 (62 ) 204,164 Total cash, cash equivalents and short-term investments $ 229,431 $ 499 $ (62 ) $ 229,868 December 31, 2018 (in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair value Cash and cash equivalents: Demand deposits and other cash $ 28,049 $ — $ — $ 28,049 Money market funds 3,737 — — 3,737 Commercial paper 2,491 — (1 ) 2,490 Corporate debt securities — — — — Total cash and cash equivalents 34,277 — (1 ) 34,276 Short-Term Investments: Commercial paper 14,091 — (11 ) 14,080 U.S. government agency securities 3,339 — (14 ) 3,325 U.S. Treasury securities 2,740 — (10 ) 2,730 Corporate debt securities 167,110 28 (379 ) 166,759 Total short-term investments 187,280 28 (414 ) 186,894 Total cash, cash equivalents and short-term investments $ 221,557 $ 28 $ (415 ) $ 221,170 The Company has determined that the unrealized losses on its short-term investments as of December 31, 2019 and 2018 do not constitute an "other than temporary impairment". The unrealized losses for the short-term investments as of December 31, 2019 and 2018 have all been in a continuous unrealized loss position for less than twelve months. The Company’s conclusion of no “other than temporary impairment” is based on the high credit quality of the securities, their short remaining maturity and the Company’s intent and ability to hold such loss securities until maturity. Classification of the cash, cash equivalent and short-term investments by contractual maturity was as follows: (in thousands) One year or shorter Between 1 and 2 years Total Balances as of December 31, 2019 Cash and cash equivalents (1) $ 25,704 $ — $ 25,704 Short-term investments 113,010 91,154 204,164 Cash, cash equivalents and short-term investments $ 138,714 $ 91,154 $ 229,868 Balances as of December 31, 2018 Cash and cash equivalents (1) $ 34,276 $ — $ 34,276 Short-term investments 109,451 77,443 186,894 Cash, cash equivalents and short-term investments $ 143,727 $ 77,443 $ 221,170 (1) Includes demand deposits and other cash, money market funds and other cash equivalent securities, all with 0-90 day maturity at purchase.

Income (loss) per share

Income (loss) per share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Income (loss) per share	oss per share The following table presents the calculation of basic and diluted net loss per share: Years ended December 31, (in thousands, except for share and per share amounts) 2019 2018 2017 Numerator: Net loss $ (17,980 ) $ (9,674 ) $ (10,897 ) Denominator: Weighted-average shares used to compute net loss per common share - basic and diluted 31,273 30,041 28,655 Net loss per share Basic and diluted $(0.57) $(0.32) $(0.38) For the years ended December 31, 2019, 2018 and 2017, the following securities were not included in the calculation of diluted shares outstanding as the effect would have been anti-dilutive: December 31, (in thousands) 2019 2018 2017 Options to purchase common stock 523 1,085 1,365 Restricted stock units 1,461 1,925 2,046

Goodwill and intangible assets

Goodwill and intangible assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and intangible assets	Goodwill and intangible assets Goodwill The Company had $49.2 million of goodwill as of December 31, 2019 and 2018 , respectively. Goodwill is tested for impairment at the reporting unit level at least annually or more often if events or changes in circumstances indicate the carrying value may not be recoverable. The Company has two reporting units: Product and Service. As of December 31, 2019 , $41.2 million of the Company's goodwill resides in the Product reporting unit and $8.0 million resides in the Service reporting unit. The Company performed an impairment assessment in 2018 which determined that no impairment existed. For the years ended December 31, 2019 and 2018, the Company used the qualitative assessment permitted under authoritative accounting guidance. Among the qualitative factors considered were changes since the prior impairment test in the following: industry and competitive environment, business strategy, product mix, buyer and supplier bargaining power, potential market size, consistency in operating margins and cash flows, change in reporting unit or product life cycle stage and earnings quality and sustainability. No impairment was recorded in the years ended December 31, 2019 , 2018 or 2017 . Intangible assets The fair values for acquired intangible assets were determined by management with consideration of, in part, valuations performed by independent valuation specialists. Acquisition-related intangible assets are amortized over the life of the assets on an accelerated basis that approximates the expected economic benefit of the assets. This assumption results in amortization that is higher in earlier periods of the useful life. The estimated useful lives and carrying value of acquired intangible assets are as follows: December 31, 2019 December 31, 2018 (in thousands) Weighted average useful life (years) Gross carrying amount Accumulated amortization Net carrying amount Gross carrying amount Accumulated amortization Net carrying amount Intangible assets: Customer relationships 7 to 9 $ 10,920 $ 5,819 $ 5,101 $ 10,920 $ 4,645 $ 6,275 Developed technology 3 to 7 10,050 9,803 247 10,050 7,731 2,319 Trademarks 3 to 7 1,110 1,110 — 1,110 831 279 Backlog 3 1,400 1,287 113 1,400 1,203 197 Non-compete agreements 2 to 4 460 460 — 460 460 — Intangible assets, net book value $ 23,940 $ 18,479 $ 5,461 $ 23,940 $ 14,870 $ 9,070 Amortization of intangible assets was $3.6 million , $4.5 million and $4.6 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. Amortization of acquired intangible assets is reflected in the cost of revenues for developed technology and backlog and in operating expenses for the other intangibles. The estimated future amortization of acquired intangible assets as of December 31, 2019 was as follows: (in thousands) Future amortization 2020 $ 1,356 2021 1,130 2022 1,050 2023 1,050 2024 875 Future amortization expense $ 5,461

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2019
Balance Sheet Components [Abstract]
Balance Sheet Components	Consolidated balance sheet components Inventories December 31, (in thousands) 2019 2018 Raw materials $ 831 $ 197 Finished goods 3,745 4,153 Total inventories $ 4,576 $ 4,350 Property and equipment, net December 31, (in thousands) 2019 2018 Computer equipment and software $ 13,596 $ 10,433 Furniture, fixtures and equipment 2,430 2,246 Leasehold improvements 5,283 5,183 Manufacturing tools and equipment 2,435 2,371 Construction in process 582 520 Property and equipment, at cost 24,326 20,753 Less: Accumulated depreciation (15,665 ) (13,285 ) Property and equipment, net $ 8,661 $ 7,468 Depreciation and amortization expense for property and equipment for the years ended December 31, 2019 , 2018 and 2017 was $3.7 million , $3.2 million and $3.0 million , respectively. Net investment in sales-type leases The Company has sales-type leases with terms of 3 to 4 years. Sales-type lease receivables are collateralized by the underlying equipment. The components of the net investment in sales-type leases are as follows: December 31, (in thousands) 2019 2018 Minimum payments to be received on sales-type leases $ 2,078 $ 2,111 Less: Unearned interest income and executory revenue portion (1,190 ) (1,387 ) Net investment in sales-type leases 888 724 Less: Current portion (452 ) (427 ) Non-current net investment in sales-type leases $ 436 $ 297 Sales-type lease activity recognized in the consolidated statement of operations are as follows: Years ended December 31, (in thousands) 2019 2018 2017 Lease revenue $ 6,394 $ 2,697 $ 2,932 Less: Cost of lease shipments (1,670 ) (212 ) (306 ) Gross profit $ 4,724 $ 2,485 $ 2,626 Interest income (expense), net on lease receivable $ (18 ) $ (6 ) $ 9 Initial direct cost incurred $ 277 $ 140 $ 167 There were no allowances for doubtful accounts on these leases as of December 31, 2019 and 2018 . There is no guaranteed or unguaranteed residual value on the leased equipment. The current and non-current net investments in sales-types leases are reported as components of the consolidated balance sheet captions "other receivables" and "other long-term assets", respectively. The minimum lease payments expected for future years under sales-type leases as of December 31, 2019 were as follows: (in thousands) Future lease payments 2020 $ 998 2021 615 2022 387 2023 78 Total $ 2,078 Accrued payroll and other current liabilities December 31, (in thousands) 2019 2018 Payroll and related expenses $ 6,053 $ 7,241 Accrued payables 2,674 2,115 Operating lease liabilities, current portion 2,323 — Lease financing, current portion 1,033 956 Product warranty 420 376 Customer prepayments 631 629 Sales and use tax payable 599 379 Other 1,024 1,189 Total accrued payroll and other current liabilities $ 14,757 $ 12,885 A reconciliation of the changes in the Company’s warranty reserve for the years ended December 31, 2019 , 2018 and 2017 is as follows: Years ended December 31, (in thousands) 2019 2018 2017 Warranty balance at the beginning of the period $ 376 $ 353 $ 596 Warranty expense accrued for shipments during the period 435 468 503 Changes in estimate related to pre-existing warranties (192 ) (223 ) (450 ) Warranty settlements made (199 ) (222 ) (296 ) Total product warranty $ 420 $ 376 $ 353 Leases The Company has operating leases for office space at its headquarters and subsidiaries under non-cancelable operating leases. Leases with an initial term of 12 months or less are not recorded on the balance sheet; lease expense for these leases is recognized on a straight-line basis over the lease term. The Company’s leases have remaining lease terms of approximately one to five years. Operating lease cost, including short-term operating leases was $2.7 million , $2.7 million and $2.6 million for the years ended December 31, 2019, 2018 and 2017, respectively. Supplemental balance sheet information related to leases was as follows: (in thousands) December 31, Other long-term assets $ 6,251 Accrued payroll and other current liabilities 2,323 Other long-term liabilities 4,866 Total operating lease liabilities $ 7,189 Other information related to leases was as follows: Year ended December 31, (in thousands) 2019 Supplemental Cash Flow Information Cash paid for amounts included in the measurement of lease liabilities $ 2,689 Right-of-use assets obtained in exchange for lease obligations $ 2,830 Weighted average remaining lease term 2.90 years Weighted average discount rate 8 % Maturities of lease liabilities as of December 31, 2019 are as follows: (in thousands) Operating leases 2020 $ 2,852 2021 3,043 2022 1,385 2023 442 2024 353 Total maturities of lease liabilities 8,075 Less imputed interest $ (886 ) Total $ 7,189 As previously disclosed in our Annual Report on Form 10-K for the fiscal year ended December 31, 2018 and under the previous lease accounting standard ASC 840, the aggregate future non-cancelable minimum rental payments on our operating leases, as of December 31, 2018, are as follows: (in thousands) Operating leases 2019 $ 2,224 2020 2,077 2021 1,835 2022 612 2023 35 Total maturities of lease liabilities $ 6,783

Commitments

Commitments	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments	Commitments and contingencies Non-cancelable purchase commitments The Company enters into non-cancelable purchase commitments with its third-party manufacturers whereby the Company is required to purchase any inventory held by the third-party manufacturer that have been purchased by them based on confirmed orders from the Company. As of December 31, 2019 and 2018 , approximately $9.7 million and $11.1 million , respectively, of raw material inventory was purchased and held by the third-party manufacturer which was subject to such purchase requirements. Litigation The Company is currently, and from time to time, the Company may be, involved in lawsuits, claims, investigations and proceedings, consisting of intellectual property, commercial, employment and other matters which arise in the ordinary course of business. The Company defends itself vigorously against any such claims. Although the outcome of these matters is currently not determinable, management expects that any losses from existing matters that are probable or reasonably possible of being incurred as a result of these matters would not be material to the financial statements as a whole.

Common stock

Common stock	12 Months Ended
	Dec. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Common Stock	Common Stock and Share-based Compensation The Company’s certificate of incorporation, as amended, authorizes the Company to issue 100 million shares of $0.0003 par value common stock. At December 31, 2019 , the Company has 2,003,979 shares of common stock reserved for issuance under stock option plans. Incentive stock option plans The Company has four equity incentive plans: the 2000 Stock Option Plan (the 2000 Plan), the 2006 Stock Option Plan (the 2006 Plan), the 2012 Stock Option Plan (the 2012 Plan) and the 2016 Equity Inducement Plan (the 2016 Plan). On March 26, 2012, all shares that were reserved under the 2006 Plan but not subject to outstanding awards became available for grant under the 2012 Plan. No additional shares will be issued under the 2006 Plan. The 2000 Plan terminated in March 2010 and no additional shares will be issued under this plan. All options currently outstanding under the 2000 Plan and the 2006 Plan continue to be governed by the terms and conditions of those plans. The 2016 Plan was adopted by the Company's Board of Directors without shareholder approval pursuant to the inducement exemption provided under the NYSE listing rules for the issuance of restricted stock units (RSUs) to employee's who joined the Company after the acquisition of Extension Healthcare. No additional shares will be issued under the 2016 Plan. Under the 2012 Plan, the Company has the ability to issue incentive stock options (ISOs), stock appreciation rights, restricted stock awards, RSUs, performance awards and stock bonuses. The ISOs will be granted at a price per share not less than the fair value at date of grant. Stock Option Activity The following table summarizes the combined stock option activity under the 2000 Plan, the 2006 Plan and the 2012 Plan and non-plan stock option agreements: Options outstanding Number of options Weighted average exercise price Weighted average remaining contractual term Aggregate intrinsic value (in years) (in thousands) Outstanding at December 31, 2018 797,501 $ 13.31 4.71 $ 20,767 Options granted — — Options exercised (187,174 ) 13.03 Options canceled (4,000 ) 10.41 Outstanding at December 31, 2019 606,327 $ 13.41 3.62 $ 4,566 Options vested and expected to vest as of December 31, 2019 606,327 $ 13.41 3.62 $ 4,566 Options vested and exercisable as of December 31, 2019 606,327 $ 13.41 3.62 $ 4,566 At December 31, 2019 , there was no unrecognized compensation cost related to options. No options were granted during the years ended December 31, 2019, 2018 and 2017. Further information regarding the value of employee options vested and exercised during the years ended December 31, 2019 , 2018 and 2017 is set forth below. Years ended December 31, (in thousands) 2019 2018 2017 Intrinsic value of options exercised during period $ 3,700 $ 10,243 $ 18,603 Employee Stock Purchase Plan The Company's 2012 Employee Stock Purchase Plan (ESPP) allows eligible employees to purchase shares of common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. The ESPP provides for six -month offering periods. At the end of each offering period, eligible employees are able to purchase shares at 85% of the lower of the fair market value of the Company's common stock on the first trading day of the offering period or on the last day of the offering period. During the years ended December 31, 2019 and 2018 , employees purchased 155,373 and 157,426 shares, respectively, of common stock at an average purchase price of $22.35 and $20.77 , respectively. As of December 31, 2019 , 873,011 shares remained available for future issuance under the ESPP. The Company uses the Black-Scholes option-pricing model to calculate the fair value of periodic ESPP offerings on their offer date. The following assumptions were used for each respective period for the ESPP: Years ended December 31, 2019 2018 2017 Expected term (in years) 0.5 0.5 0.5 Volatility 33% - 50% 33% - 37.8% 29.0% - 32.0% Risk-free interest rate 1.59% - 2.51% 2.09% - 2.51% 0.61% - 1.39% Dividend yield 0.0% 0.0% 0.0% Restricted Stock Units The Company issues RSUs as an element of its compensation plans. A summary of the restricted stock activity for the year ended December 31, 2019 is presented below: Restricted Stock Units Number of shares Weighted Average Grant Date Fair Value per Share Outstanding at December 31, 2018 1,807,180 $ 23.13 Granted 845,437 31.88 Vested (978,785 ) 20.89 Forfeited (123,186 ) 27.78 Outstanding at December 31, 2019 1,550,646 $ 28.94 At December 31, 2019 , there was $30.2 million of unrecognized compensation cost related to RSUs, which is expected to be recognized over a weighted-average period of 1.65 years. Allocation of Stock-Based Compensation Expense Stock-based compensation expense is recognized based on a straight-line amortization method over the respective vesting period of the award. For the years ended December 31, 2019, 2018 and 2017 the straight-line amortization is reduced by actual forfeitures. The Company estimated the expected forfeiture rate based on its historical experience, considering voluntary termination behaviors, trends of actual award forfeitures, and other events that will impact the forfeiture rate. To the extent the Company’s actual forfeiture rate is different from the estimate, the stock-based compensation expense is adjusted accordingly. The following table presents the allocation of stock-based compensation expense: Years ended December 31, (in thousands) 2019 2018 2017 Cost of revenue $ 4,441 $ 3,614 $ 2,871 Research and development 3,955 2,976 2,122 Sales and marketing 7,014 6,560 6,563 General and administrative 8,455 7,814 6,640 Total stock-based compensation $ 23,865 $ 20,964 $ 18,196

Segments

Segments	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segments	Segments The Company has two operating segments which are both reportable segments: (i) Product; and (ii) Service, which are comprised of the Company’s and its wholly-owned subsidiaries’ results from operations. Operating segments are defined as components of an enterprise about which separate financial information is available that is evaluated regularly by the chief operating decision maker (CODM), or decision-making group, in deciding how to allocate resources and in assessing performance. The Company’s CODM is its Chief Executive Officer. The CODM regularly receives information related to revenue, cost of revenue, and gross profit for each operating segment, and uses this information to assess performance and make resource allocation decisions. All other financial information, including operating expenses and assets, is prepared and reviewed by the CODM on a consolidated basis. Assets are not a measure used to assess the performance of the Company by the CODM, therefore the Company does not report assets by segment internally or in its financial statements. The following table presents a summary of the operating segments: Years ended December 31, (in thousands) 2019 2018 2017 Revenue Product $ 92,561 $ 97,447 $ 91,585 Service 87,940 82,183 74,404 Total revenue 180,501 179,630 165,989 Cost of revenue Product 29,039 27,425 27,244 Service 42,363 40,318 37,683 Total cost of revenue 71,402 67,743 64,927 Gross profit Product 63,522 70,022 64,341 Service 45,577 41,865 36,721 Total gross profit 109,099 111,887 101,062 Operating expenses 123,222 118,192 111,762 (Loss) income from operations (14,123 ) (6,305 ) (10,700 ) Interest income (expense), net and other (3,837 ) (3,720 ) 562 Loss before income taxes $ (17,960 ) $ (10,025 ) $ (10,138 ) The following tables present the Company’s revenue by product line, as well as revenue and long-lived assets by geographic region. Years ended December 31, (in thousands) 2019 2018 2017 Revenue Product Device $ 61,224 $ 60,130 $ 61,746 Software 31,337 37,317 29,839 Total product 92,561 97,447 91,585 Service Maintenance and support 68,846 62,267 52,342 Professional services and training 19,094 19,916 22,062 Total service 87,940 82,183 74,404 Total revenue $ 180,501 $ 179,630 $ 165,989 The Company’s revenue by geographic region, based on customer location, is summarized as follows: Years ended December 31, (in thousands) 2019 2018 2017 Revenue United States $ 164,827 $ 161,338 $ 148,993 International 15,674 18,292 16,996 Total revenue $ 180,501 $ 179,630 $ 165,989 The Company’s tangible long-lived assets by geographic region, consisting of net property and equipment, are summarized as follows: December 31, (in thousands) 2019 2018 2017 Property and equipment, net United States $ 6,364 $ 6,265 $ 4,621 International 2,297 1,203 1,130 Total property and equipment, net $ 8,661 $ 7,468 $ 5,751

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income taxes The components of loss before income taxes are as follows: Years ended December 31, (in thousands) 2019 2018 2017 United States $ (19,022 ) $ (10,852 ) $ (10,930 ) International 1,062 827 792 Total loss before income taxes $ (17,960 ) $ (10,025 ) $ (10,138 ) The components of the provision for income taxes are as follows: Years ended December 31, (in thousands) 2019 2018 2017 Current Federal $ — $ — $ (10 ) State (25 ) 53 54 Foreign 240 368 324 215 421 368 Deferred Federal (43 ) (822 ) 311 State 7 99 119 Foreign (159 ) (49 ) (39 ) (195 ) (772 ) 391 Total income tax provision (benefit) $ 20 $ (351 ) $ 759 The Company had an effective tax rate of 0.1% , (3.5)% and 7.5% for the years ended December 31, 2019 , 2018 and 2017 , respectively. Reconciliation of the provision for income taxes at the statutory rate to the Company’s provision for income tax is as follows: Years ended December 31, (in thousands) 2019 2018 2017 U.S. federal (tax benefit) provision at statutory rate $ (3,772 ) $ (2,105 ) $ (4,576 ) State (tax benefit) income taxes, net of federal benefit (646 ) (373 ) (437 ) Foreign income taxes at rates other than the US rate (145 ) 92 (21 ) Stock-based compensation (2,119 ) (3,503 ) (8,373 ) Change in valuation allowance 5,136 4,710 (6,023 ) Non-deductible executive compensation 2,383 2,418 1,624 Rate differential impact on Tax Cuts and Jobs Act — — 18,975 Research and development credits (1,209 ) (994 ) (602 ) Indefinite net operating losses carryforward (33 ) (1,470 ) — Other 425 874 192 Total $ 20 $ (351 ) $ 759 Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The following table presents the significant components of the Company’s deferred tax assets and liabilities for the periods presented: December 31, (in thousands) 2019 2018 Deferred tax assets Net operating loss carryforward $ 32,723 $ 29,798 Research and development credits 8,449 6,840 Depreciation and amortization 2,402 3,007 Reserves and accruals 9,349 9,661 Total deferred tax assets 52,923 49,306 Valuation allowance (40,436 ) (40,070 ) Net deferred tax assets 12,487 9,236 Deferred tax liabilities - convertible senior notes (5,848 ) (7,503 ) Deferred tax liabilities - other (7,097 ) (2,208 ) Net deferred tax liabilities $ (458 ) $ (475 ) The Company's deferred tax liabilities are primarily related to tax deductible goodwill. The Company determines its valuation allowance on deferred tax assets by considering both positive and negative evidence in order to ascertain whether it is more likely than not that deferred tax assets will be realized. Realization of deferred tax assets is dependent upon the generation of future taxable income, if any, the timing and amount of which are uncertain. Due to the history of losses the Company has generated in the past, the Company believes that it is not more likely than not that all of the deferred tax assets in the U.S. and Canada can be realized as of December 31, 2019 ; accordingly, the Company has recorded a full valuation allowance on its deferred tax assets. The Company’s valuation allowance increased by $0.4 million and $5.2 million for the years ended December 31, 2019 and 2018 , respectively. The change in the 2019 valuation allowance was primarily due to the addition of current year loss carryforwards and federal rate reduction. The change in the 2018 valuation allowance was primarily due to the addition of current year loss carryforwards. At December 31, 2019 , the Company had $137 million and $69 million , respectively, of federal and state net operating loss carryforwards. The federal net operating loss carryforward generated in the years ended December 31, 2002 through 2017 begin expiring in 2022. Net operating losses originating before January 1, 2018 are eligible to offset taxable income, if not otherwise limited under IRS Section 382. Net operating losses generated after December 31, 2017 have an infinite carryforward period and subject to 80% deduction limitation based upon pre-net operating deduction taxable income. The state net operating loss carryforward begins expiring in 2028, if not utilized. In addition, the Company has federal research and development tax credits carryforwards of approximately $5.3 million and state research and development tax credit carryforwards of approximately $5.9 million . The federal credit carryforwards begin expiring 2026 and the state credits carry forward indefinitely . The Internal Revenue Code (IRC) contains provisions which limit the amount of net operating loss (NOL) and research credit carryforwards that can be used in any given year if a significant change in ownership has occurred. As of December 31, 2019, $11.5 million of the Company's NOL carryovers and $0.5 million of credit carryovers are subject to an annual $0.6 million limitation, of which $5.3 million NOLs would be available to offset future taxable income in the twenty-year carryforward period. The following table displays by contributing factor the changes in the valuation allowance for deferred tax assets since January 1, 2017: Years Ended December 31, (in thousands) 2019 2018 2017 Balance at the beginning of the period $ 40,070 $ 45,255 $ 42,339 Net operating loss carryforwards generated 2,925 2,509 3,050 R&D tax credit increase 1,609 1,014 1,121 Depreciation and amortization increase (605 ) 925 237 Reserves and accruals decrease (312 ) (581 ) (1,479 ) Deferred tax assets increase (3,251 ) (9,052 ) (13 ) Balance at the end of the period $ 40,436 $ 40,070 $ 45,255 The following table reflects changes in the unrecognized tax benefits since January 1, 2018: Years ended December 31, (in thousands) 2019 2018 Gross amount of unrecognized tax benefits as of the beginning of the period $ 1,931 $ 1,673 Increases related to prior year tax provisions — 7 Decreases related to prior year tax provisions (78 ) — Increases related to current year tax provisions 398 251 Gross amount of unrecognized tax benefits as of the end of the period $ 2,251 $ 1,931 As a result of the Company’s historical losses and related valuation allowances, the Company has recorded substantially all of the uncertain tax amounts above as reductions to deferred tax assets which are subject to a full valuation allowance in its consolidated balance sheet with an insignificant portion recorded in other long-term liabilities. The Company recognizes interest and penalties relating to uncertain tax positions in income tax expense. As the Company is not currently under examination, it is reasonable to assume that the balance of gross unrecognized tax benefits will likely not change in the next twelve months. The Company files income tax returns in the United States on a federal basis and in various states. The Company is not currently under any international or any United States federal, state and local income tax examinations for any taxable years. All of the Company’s net operating losses and research credit carryforwards prior to 2019 are subject to tax authority adjustment and all years after 2012 are still subject to the tax authority examinations. The 2017 tax reform legislation provides for a one-time “deemed repatriation” of accumulated foreign earnings for the year ended December 31, 2017. The Company does not expect to pay U.S. federal cash taxes on the deemed repatriation due to its historical net operating loss for tax purposes. The Company does not expect that the future foreign earnings will be subject to U.S. federal income tax since the Company intends to continue reinvesting such earnings outside the U.S. indefinitely. On December 22, 2017, the SEC issued Staff Accounting Bulletin 118 (“SAB 118”), which provides guidance on accounting for tax effects of the Tax Act. SAB 118’s measurement period closed on December 22, 2018, one year from the Tax Act enactment. The Company completed its accounting for the impact of the Tax Act and there were no subsequent revisions from the provisional amounts recorded in the prior year financial statements.

Quarterly results of operations

Quarterly results of operations (unaudited) (Notes)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly results of operations (unaudited)	Quarterly results of operations (unaudited) The following tables present certain unaudited consolidated quarterly financial information for each of the eight quarters ended December 31, 2019 . This quarterly information has been prepared on the same basis as the consolidated financial statements and includes all adjustments necessary to state fairly the information for the periods presented. (In thousands, except per share data) Quarters Ended 2019 March 31, June 30, September 30, December 31, Total revenue $ 35,309 $ 44,759 $ 50,781 $ 49,652 Gross profit $ 19,685 $ 27,016 $ 31,888 $ 30,510 Net income (loss) $ (11,735 ) $ (4,857 ) $ 298 $ (1,686 ) Net income (loss) attributable to common stockholders $ (11,735 ) $ (4,857 ) $ 298 $ (1,686 ) Net income (loss) per share attributable to common stockholders: Basic $ (0.38 ) $ (0.16 ) $ 0.01 $ (0.05 ) Diluted $ (0.38 ) $ (0.16 ) $ 0.01 $ (0.05 ) Weighted average shares used to compute net income (loss) per share attributable to common stockholders: Basic 30,800 31,242 31,459 31,579 Diluted 30,800 31,242 31,944 31,579 Quarters Ended 2018 March 31, June 30, September 30, December 31, Total revenue $ 40,242 $ 42,686 $ 47,822 $ 48,880 Gross profit $ 23,901 $ 25,651 $ 31,138 $ 31,197 Net income (loss) $ (4,770 ) $ (3,554 ) $ (249 ) $ (1,101 ) Net income (loss) attributable to common stockholders $ (4,770 ) $ (3,554 ) $ (249 ) $ (1,101 ) Net loss per share attributable to common stockholders: Basic and Diluted $ (0.24 ) $ (0.26 ) $ (0.01 ) $ (0.04 ) Weighted average shares used to compute net loss per common share: Basic and diluted 29,476 29,867 29,861 30,592

The Company and Summary of Si_2

The Company and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	Recently adopted accounting pronouncement In February 2016, the FASB amended lease accounting requirements to begin recording assets and liabilities arising from leases on the balance sheet. The new guidance requires significant additional disclosures about the amount, timing and uncertainty of cash flows from leases. We adopted this new guidance effective January 1, 2019 using a modified retrospective approach. The modified retrospective approach includes a number of optional practical expedients that entities may elect to apply. The Company elected the package of practical expedients permitted under the transition guidance within the new standard. The adoption of the standard resulted in recognition of right-of-use assets, which includes the impact of existing deferred rents and tenant improvement allowances of $5.1 million and lease liabilities of $6.7 million as of January 1, 2019. The standard did not affect our consolidated net earnings or cashflows. In February 2018, the FASB issued new guidance which allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act and required certain disclosures about stranded tax effects. We adopted this standard effective January 1, 2019 on a prospective basis. The adoption of this guidance did not have an impact on the Company’s consolidated financial statements. In August 2018, the SEC adopted the final rule under SEC Release No. 33-10532, Disclosure Update and Simplification, amending certain disclosure requirements that were redundant, duplicative, overlapping, outdated or superseded. In addition, the amendments expanded the disclosure requirements on the analysis of stockholders' equity for interim financial statements. Under the amendments, an analysis of changes in each caption of stockholders' equity presented in the balance sheet must be provided in a note or separate statement. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a statement of comprehensive income is required to be filed. This final rule was effective on November 5, 2018. The Company adopted this guidance in the first quarter of fiscal year 2019. The adoption of this guidance did not have an impact on the Company's consolidated financial statements.
Basis of Presentation	Basis of presentation The consolidated financial statements include the accounts of Vocera Communications, Inc. and its wholly owned subsidiaries. All inter-company transactions and balances have been eliminated in consolidation. The accompanying notes are prepared in accordance with accounting principles generally accepted in the United States (GAAP).
Consolidation	The consolidated financial statements include the accounts of Vocera Communications, Inc. and its wholly owned subsidiaries. All inter-company transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of estimates and reclassifications The preparation of financial statements in conformity with GAAP requires the Company 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 financial statements and the reported amounts of revenue and expense during the reporting periods. The estimates include, but are not limited to, revenue recognition, warranty reserves, inventory reserves, bonuses, goodwill and intangible assets, stock-based compensation expense, provisions for income taxes and contingencies. Actual results could differ from these estimates, and such differences could be material to the Company’s financial position and results of operations.
Cash, Cash Equivalents and Short-term Investments	Cash, cash equivalents and short-term investments The Company’s cash equivalents and short-term investments consist of money market funds, commercial paper, U.S. government agency notes, U.S. Treasury notes and corporate debt. These investments are classified as available-for-sale securities and are carried at fair value with the unrealized gains and losses reported as a component of stockholders’ equity. Management determines the appropriate classification of its investments at the time of purchase and re-evaluates the available-for-sale designations as of each balance sheet date. Investments with an original purchase maturity of three months or less are classified as cash equivalents, all those with longer maturities are classified as short-term investments, which are available-for-sale.
Allowance for Doubtful Accounts	Allowance for doubtful accounts The allowance for doubtful accounts reflects the Company’s best estimate of probable losses inherent in the Company’s receivables portfolio determined on the basis of historical experience, specific allowances for known troubled accounts and other currently available evidence. The Company has not experienced significant credit losses from its accounts receivable. The Company performs a regular review of its customers’ payment histories and associated credit risks as it does not require collateral from its customers. No allowance for doubtful accounts was recorded in the years ended December 31, 2019, 2018 or 2017.
Inventories	Inventories Inventories are valued at the lower of standard cost (which approximates actual cost on a first-in, first-out basis) or market (net realizable value or replacement cost). The Company assesses the valuation of inventory and periodically writes down the value for estimated excess and obsolete inventory based upon assumptions about future demand and market conditions.
Concentration of credit risk and other risks and uncertainties	Concentration of credit risk and other risks and uncertainties Financial instruments that subject the Company to concentration of credit risk consist primarily of cash, cash equivalents and short-term investments. The Company’s cash and cash equivalents are primarily deposited with high quality financial institutions and in money market funds. Deposits at these institutions and funds may, at times, exceed federally insured limits. Management believes that these financial institutions and funds are financially sound and, accordingly, that minimal credit risk exists. The Company has not experienced any losses on its deposits of cash and cash equivalents. Marketable securities are stated at fair value and accounted for as available-for-sale within short-term investments. The counterparties to the agreements relating to the Company’s investment securities consist of major corporations, financial institutions and government agencies of high credit standing. The primary hardware components of the Company’s products are currently manufactured by third-party contractors in Mexico and Taiwan. A significant disruption in the operations of these contractors may impact the production of the Company’s products for a substantial period of time, which could harm the Company’s business, financial condition and results of operations. Concentration of credit risk with respect to trade accounts receivable is considered to be limited due to the diversity of the Company’s customer base and geographic sales areas. At December 31, 2019 and 2018 , no customer accounted for 10% or more of accounts receivable. At December 31, 2019 and 2018, one reseller represented 19.3% and 26.4% , respectively of accounts receivable. For the years ended December 31, 2019 , 2018 and 2017 , no customer represented 10% or more of revenue.
Property and Equipment	Property and equipment Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful economic lives of the assets. Assets generally have useful economic lives of three years except for leasehold improvements, which are amortized using the straight-line method over the shorter of the remaining lease term or the estimated useful life of the related assets. Purchased software also generally has a useful economic life of three years , except for major ERP implementations, for which the Company assumes a useful economic life of five years . Upon retirement or sale, the cost and related accumulated depreciation and amortization are removed from the consolidated balance sheet and the resulting gain or loss is reflected in operations. Maintenance and repairs which are not considered improvements and do not extend the useful life of the assets are charged to operations as incurred. The Company periodically reviews property and equipment for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset is impaired or the estimated useful lives are no longer appropriate. Fair value is estimated based on undiscounted future cash flows. If indicators of impairment exist and the undiscounted projected cash flows associated with such assets are less than the carrying amount of the asset, an impairment loss is recorded to write the asset down to its estimated fair values. To date, the Company has not recorded any impairment charges.
Software Development Costs	oftware development costs For internal-use software, the Company capitalizes certain internal and external costs incurred in its acquisition and creation. Capitalized internal-use software is included in property and equipment amortized on a straight-line basis over the estimated useful life of the related asset, generally three years . Based on the authoritative guidance, costs incurred either before or after the period satisfying the capitalization criteria, together with costs incurred for training and maintenance, are expensed as incurred. For the years ended December 31, 2019 , 2018 and 2017 , the Company capitalized costs of $0.6 million , $0.7 million and $0.3 million , respectively.
Goodwill and Intangible Assets	Goodwill and intangible assets The Company allocates the purchase price of any acquisitions to tangible assets and liabilities and identifiable intangible assets acquired. Any residual purchase price is recorded as goodwill. Goodwill Goodwill is tested for impairment at the reporting unit level at least annually, or more often if events or changes in circumstances indicate the carrying value may not be recoverable. The Company has identified two operating segments (Product and Service) which management also considers to be reporting units. In testing for goodwill impairment, the Company may elect to utilize a qualitative assessment to evaluate whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If such qualitative assessment indicates that goodwill impairment is more likely than not, the Company performs a two- step impairment test. The Company performed its goodwill impairment assessment on October 1, 2019 using a qualitative assessment and determined that no impairment existed as of the date of the impairment test because the fair value of each reporting unit more likely than not exceeded its carrying value. As of December 31, 2019 , no changes in circumstances indicate that goodwill carrying values may not be recoverable. Intangible assets Intangible assets are amortized over their estimated useful lives. Upon completion of development, acquired in-process research and development assets are generally considered amortizable, finite-lived assets and are amortized over their estimated useful lives. Finite-lived intangible assets consist of customer relationships, developed technology, trademarks, backlog and non-compete agreements. The Company evaluates intangible assets for impairment by assessing the recoverability of these assets whenever adverse events or changes in circumstances or business climate indicate that expected undiscounted future cash flows related to such intangible assets may not be sufficient to support the net book value of such assets. An impairment is recognized in the period of identification to the extent the carrying amount of an asset exceeds the fair value of such asset. No impairment of intangible assets was recorded in the years ended December 31, 2019 , 2018 or 2017 .
Operating leases [Policy Text Block]	Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in other long-term assets, accrued payroll and other current liabilities and other long-term liabilities on the consolidated balance sheets. Sales-type leases are included in other receivables, accrued payroll and other current liabilities and other long-term liabilities on the consolidated balance sheets. The Company has elected an accounting policy to not recognize short-term leases (one year or less) on the consolidated balance sheet. The Company also elected the package of practical expedients which applies to leases that commenced before the adoption date. By electing the package of practical expedients, the Company did not need to reassess whether any existing contracts are or contained a lease or the lease classification for any existing leases. Operating lease right-of-use assets and operating lease liabilities are recognized based on the present value of the lease payments over the lease term at commencement date. As most of the Company’s leases do not provide an implicit rate, the incremental borrowing rate is used based on the information available at commencement date in determining the present value of future payments. For those leases that existed as of January 1, 2019, we used our incremental borrowing rate based on information available at that date. We apply a portfolio approach for determining the incremental borrowing rate based on the applicable lease terms and the current economic environment and we utilize available information regarding our borrowing rates. The operating lease right-of-use asset also includes any lease payments made 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 minimum lease payments is recognized on a straight-line basis over the lease term. The Company accounts for lease components and nonlease components as a single lease component.
Revenue Recognition, Policy	Shipping and handling costs Shipping and handling costs charged to customers are included in revenue and the associated expense is recorded in cost of revenue in the consolidated statements of operations for all periods presented. Revenue recognition The core principle of ASC 606 is to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This principle is achieved through applying the following five-step approach: • Identification of the contract, or contracts, with a customer - A contract with a customer exists when (i) the Company enters into an enforceable contract with a customer that defines each party’s rights regarding the goods or services to be transferred and identifies the payment terms related to these goods or services, (ii) the contract has commercial substance and, (iii) the Company determines that collection of substantially all consideration for goods or services that are transferred is probable based on the customer’s intent and ability to pay the promised consideration. The Company applies judgment in determining the customer’s ability and intention to pay, which is based on a variety of factors including the customer’s historical payment experience or, in the case of a new customer, published credit and financial information pertaining to the customer. Customer payments received by the Company are non-refundable. • Identification of the performance obligations in the contract - Performance obligations promised in a contract are identified based on the goods or services that will be transferred to the customer that are capable of being both: a) functionally distinct, whereby the customer can benefit from the goods or service either on their own or together with other resources that are readily available from third parties or from the Company, and b) contractually distinct, whereby the transfer of the goods or services is separately identifiable from other promises in the contract. To the extent a contract includes multiple promised goods or services, the Company applies judgment to determine whether promised goods or services are capable of being distinct and distinct in the context of the contract. If these criteria are not met the promised goods or services are accounted for as a combined performance obligation. • Determination of the transaction price - The transaction price is determined based on the consideration to which the Company will be entitled in exchange for transferring goods or services to the customer. • Allocation of the transaction price to the performance obligations in the contract - If the contract contains a single performance obligation, the entire transaction price is allocated to the single performance obligation. Contracts that contain multiple performance obligations require an allocation of the transaction price to each performance obligation based on a relative standalone selling price, (SSP) basis. The Company determines standalone selling price based on the price at which the performance obligation is sold separately. If the standalone selling price is not observable through past transactions, the Company estimates the standalone selling price taking into account available information such as market conditions and internally approved pricing guidelines related to the performance obligations. • Recognition of revenue when, or as, the Company satisfies a performance obligation - The Company satisfies performance obligations either over time or at a point in time as discussed in further detail below. Revenue is recognized at the time the related performance obligation is satisfied by transferring a promised good or service to a customer. Device revenue - In transactions where the Company delivers hardware, the Company considers itself to be the principal in the transaction and records revenue and costs of goods sold on a gross basis. Hardware revenue is generally recognized upon transfer of control to the customer. Software revenue - Revenue from the Company’s software products is generally recognized upon transfer of control to the customer. Additional software revenue is derived from the sale of term licenses and cloud-based subscriptions, which can be renewed on a subscription basis. Revenue is generally recognized upon shipment of hardware and perpetual licenses and, in the case of subscription software, ratably over the applicable term. Maintenance and support revenue - The Company generates maintenance and support revenue primarily from post contract support (PCS) contracts, and, to a lesser extent, from sales of extended warranties on the Vocera Badge. The majority of software sales are in conjunction with PCS contracts, which generally have one-year terms. The Company recognizes revenue from PCS contracts ratably over the contractual service period. The service period typically commences upon transfer of control of the corresponding software products to the customer. The Company recognizes revenue from extended warranty contracts ratably over their contractual service period, which is primarily two years . This period starts one year from the date on which the transfer of control on the underlying hardware occurs because the hardware generally carries a one-year warranty. Professional services and training revenue - Professional services and training revenue is generated when the Company installs and configures its software and devices at new or existing customer sites. The Company recognizes revenue related to professional services as they are performed. Contracts with multiple performance obligations - Some of the Company’s contracts with customers contain multiple performance obligations. For these contracts, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to the separate performance obligations on a relative stand-alone selling price basis. For deliverables that are routinely sold separately, such as maintenance and support on the core offerings, the Company determines SSP by evaluating renewals over the trailing 12-months. For those that are not sold routinely, the Company determines SSP based on its overall pricing trends and objectives, taking into consideration market conditions and other factors, including the value of the contracts and the products sold. Contract balances - The timing of revenue recognition may differ from the timing of invoicing to customers. Accounts receivable are recorded at the invoiced amount and in the period the Company delivers goods or provides services or when the Company’s right to consideration is unconditional. Payment terms on invoiced amounts are typically 30 days . The balance of accounts receivable, net of allowance for doubtful accounts, as of December 31, 2019 and 2018 is presented in the accompanying consolidated balance sheets. In situations where revenue recognition occurs before invoicing, an unbilled receivable is created, which represents a contract asset. As of December 31, 2019 and 2018 contract assets totaling $4.3 million and $2.4 million , respectively, were included in other receivables in the consolidated balance sheet. Revenue from sales-type leases A portion of the Company's sales are made through multi-year lease agreements with customers. When these arrangements are considered sales-type leases, upon delivery of leased products to customers, the Company recognizes revenue for such products in an amount equal to the net present value of the minimum lease payments. Unearned income is recognized as part of product revenue under the effective interest method. The Company recognizes revenue related to certain executory costs, including maintenance and extended warranty, ratably over the term of the underlying arrangements. The Company recognizes revenue related to battery refresh executory costs when such executory costs are incurred. Proceeds from transfers of sales-type leases to third-party financial companies are allocated between the net investment in sales-type leases and the executory cost component for remaining service obligations based on relative present value. The difference between the amount of proceeds allocated to the net investment in lease and the carrying value of the net investment in lease is included in product revenue. Proceeds allocated to the executory cost component are accounted for as financing liabilities. For the year ended December 31, 2019 , the Company transferred $3.5 million of lease receivables, recording a net loss of $0.3 million and $1.7 million of new financing liabilities for future performance of executory service obligations. For the year ended December 31, 2018 , the Company transferred $0.4 million of lease receivables, recording an immaterial net loss and $0.3 million of new financing liabilities for future performance of executory service obligations. For lease receivables retained as of December 31, 2019 and 2018 , the Company recorded $0.9 million and $0.7 million , respectively, of net investment in sales-type leases, equivalent to the minimum lease payments for the delivered product.
Revenue Recognition, sales type leases	Revenue from sales-type leases A portion of the Company's sales are made through multi-year lease agreements with customers. When these arrangements are considered sales-type leases, upon delivery of leased products to customers, the Company recognizes revenue for such products in an amount equal to the net present value of the minimum lease payments. Unearned income is recognized as part of product revenue under the effective interest method. The Company recognizes revenue related to certain executory costs, including maintenance and extended warranty, ratably over the term of the underlying arrangements. The Company recognizes revenue related to battery refresh executory costs when such executory costs are incurred. Proceeds from transfers of sales-type leases to third-party financial companies are allocated between the net investment in sales-type leases and the executory cost component for remaining service obligations based on relative present value. The difference between the amount of proceeds allocated to the net investment in lease and the carrying value of the net investment in lease is included in product revenue. Proceeds allocated to the executory cost component are accounted for as financing liabilities. For the year ended December 31, 2019 , the Company transferred $3.5 million of lease receivables, recording a net loss of $0.3 million and $1.7 million of new financing liabilities for future performance of executory service obligations. For the year ended December 31, 2018 , the Company transferred $0.4 million of lease receivables, recording an immaterial net loss and $0.3 million of new financing liabilities for future performance of executory service obligations. For lease receivables retained as of December 31, 2019 and 2018 , the Company recorded $0.9 million and $0.7 million , respectively, of net investment in sales-type leases, equivalent to the minimum lease payments for the delivered product.
Research and Development Expenditures	Research and development expenditures Research and development costs are charged to operations as incurred. Software development costs incurred for external products prior to the establishment of technological feasibility are included in research and development and are expensed as incurred. After technological feasibility is established, material software development costs up to general availability of the software will be capitalized and amortized on a straight-line basis over the estimated product life, or based on the ratio of current revenues to total projected product revenue, whichever is greater. To date, the time between the establishment of technological feasibility and general availability has been very short and therefore no significant costs have been incurred. Accordingly, the Company has not capitalized any software development costs related to research and development expenditures.
Advertising Costs	Advertising costs Advertising costs are included in sales and marketing expense and are expensed as incurred. Advertising costs for the years ended December 31, 2019 , 2018 and 2017 were immaterial.
Product Warranties	Product warranties The Company offers warranties on certain products and records a liability for the estimated future costs associated with warranty claims, which is based upon historical experience and the Company’s estimate of the level of future costs. The Company provides for the estimated costs of hardware warranties at the time the related revenue is recognized. Costs are estimated based on historical and projected product failure rates, historical and projected repair costs, and knowledge of specific product failures (if any). The specific hardware warranty includes parts and labor over a period generally ranging from one to three years. The Company provides no warranty for software. The Company regularly re-evaluates its estimates to assess the adequacy of the recorded warranty liabilities and adjust the amounts as necessary. Warranty costs are reflected in the consolidated statement of operations as cost of revenue.
Product Warranties	A reconciliation of the changes in the Company’s warranty reserve for the years ended December 31, 2019 , 2018 and 2017 is as follows: Years ended December 31, (in thousands) 2019 2018 2017 Warranty balance at the beginning of the period $ 376 $ 353 $ 596 Warranty expense accrued for shipments during the period 435 468 503 Changes in estimate related to pre-existing warranties (192 ) (223 ) (450 ) Warranty settlements made (199 ) (222 ) (296 ) Total product warranty $ 420 $ 376 $ 353
Stock-based Compensation	Stock-based compensation Stock-based compensation is measured at grant date based on the fair value of the award using the grant date closing stock price and is expensed on a straight-line basis over the requisite service period.
Income Taxes	Income taxes The Company uses the asset and liability method of accounting for income taxes. Under this method, the Company records deferred income taxes based on temporary differences between the financial reporting and tax bases of assets and liabilities and use enacted tax rates and laws that the Company expects will be in effect when they recover those assets or settle those liabilities, as the case may be, to measure those taxes. In cases where the expiration date of tax carryforwards or the projected operating results indicate that realization is not likely, the Company provides for a valuation allowance. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized. The Company has deferred tax assets, resulting from net operating losses, research and development credits and temporary differences that may reduce taxable income in future periods. A valuation allowance is required when it is more likely than not that all or a portion of a deferred tax asset will not be realized. In assessing the need for a valuation allowance, the Company estimates future taxable income, considering the feasibility of ongoing tax-planning strategies and the realizability of tax loss carryforwards. Valuation allowances related to deferred tax assets can be impacted by changes in tax laws, changes in statutory tax rates and future taxable income levels. If the Company were to determine that it would be able to realize its deferred tax assets in the future in excess of the net carrying amounts, it would decrease the recorded valuation allowance through an increase to income in the period in which that determination is made. Due to the history of losses the Company has generated in the past, the Company believes that it is not more likely than not that all of the deferred tax assets in the U.S. and Canada can be realized as of December 31, 2019 and 2018, respectively. Accordingly, the Company has recorded a full valuation allowance on its deferred tax assets for these years. At December 31, 2019 , the Company had a valuation allowance against net deferred tax assets of $40.4 million . There is inherent uncertainty in evaluating the sustainability of the income tax positions the Company takes on its tax returns. The Company assesses its income tax positions and records tax benefits for all years subject to examination based upon management’s evaluation of the facts, circumstances and information available at the reporting date. For those tax positions where it is more likely than not that a tax benefit will be sustained, the Company has recorded the highest amount of tax benefit with a greater than 50% likelihood of being realized upon ultimate settlement with a taxing authority that has full knowledge of all relevant information. For those income tax positions where it is not more likely than not that a tax benefit will be realizable, no tax benefit has been recognized in the financial statements. The Company includes interest and penalties with income taxes in the accompanying statement of operations. All of the Company’s net operating losses and research credit carryforwards are subject to adjustment by tax authorities and all years after 2012 are still subject to tax authority examinations. The Company is currently not subject to any income tax audit examinations by tax authorities in any jurisdictions including U.S. federal, state and local or foreign countries.
Foreign Currency Translation	Foreign currency translation
Segments	Segments
Comprehensive Income (Loss)	Comprehensive loss For the years ended December 31, 2019 , 2018 and 2017, the only component of other comprehensive loss was unrealized (losses) gains on available-for-sale securities.
Related Party Transactions Disclosure	Related party transactions During the years ended December 31, 2019 , 2018 and 2017 , the Company had revenue transactions with a related party, the University of Chicago Medical Center (UCMC), for $1.3 million , $0.4 million and $0.4 million , respectively, relating to consulting services and technology solutions. One of the Company's board members is the President of UCMC.
Recent Accounting Pronouncements	Recent accounting pronouncements In June 2016, the FASB issued new guidance related to the accounting for credit losses on instruments for both financial services and non-financial services entities. The new guidance introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. It also modifies the impairment model for available-for-sale debt securities and provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. The guidance will be effective for us beginning January 1, 2020. Early adoption is permitted. The Company is currently evaluating the impact of this new guidance on its consolidated financial statements. In January 2017, the FASB issued new guidance to simplify the accounting for goodwill impairment. The guidance simplifies the measurement of goodwill impairment by removing step 2 of the goodwill impairment test, which requires the determination of the fair value of individual assets and liabilities of a reporting unit. The new guidance requires goodwill impairment to be measured as the amount by which a reporting unit’s carrying value exceeds its fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The amendments should be applied on a prospective basis. The new standard is effective for fiscal years beginning after December 15, 2019 with early adoption permitted for interim or annual goodwill impairment tests performed after January 1, 2017. The Company is evaluating the impact of this new accounting guidance on its consolidated financial statements.

Convertible Senior Notes (Table

Convertible Senior Notes (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Notes	The Notes consist of the following: (in thousands) December 31, December 31, Liability: Principal $ 143,750 $ 143,750 Unamortized debt discount (23,880 ) (29,846 ) Unamortized issuance costs (2,692 ) (3,364 ) Net carrying amount $ 117,178 $ 110,540 Stockholders’ equity: Debt discount for conversion option $ 33,350 $ 33,350 Issuance costs $ (1,136 ) $ (1,136 ) Net carrying amount $ 32,214 $ 32,214
Schedule of Interest Expense Related to the Notes	Interest expense related to the Notes is as follows: Year ended December 31, (in thousands) 2019 2018 Contractual interest expense $ 2,150 $ 1,342 Amortization of debt discount 5,966 3,504 Amortization of issuance costs 673 395 Total interest expense $ 8,789 $ 5,241
Schedule of Net Impact on Stockholders' Equity of Components of Convertible Debt	The net impact to the Company’s stockholders' equity, included in additional paid-in capital, of the above components of the Notes is as follows: (in thousands) December 31, Conversion option $ 33,350 Purchase of capped calls $ (8,907 ) Issuance costs $ (1,136 ) Total $ 23,307

The Company and Summary of Si_3

The Company and Summary of Significant Accounting Policies The Company and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Allowance for Credit Losses on Financing Receivables [Table Text Block]

Fair value of financial instr_2

Fair value of financial instruments (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of assets and liabilities measured at fair value on a recurring basis, by level	he table below summarizes the Company’s assets that are measured at fair value on a recurring basis, by level, within the fair value hierarchy as of December 31, 2019 and 2018 , respectively. December 31, 2019 December 31, 2018 (in thousands) Level 1 Level 2 Total Level 1 Level 2 Total Assets Money market funds $ 4,086 $ — $ 4,086 $ 3,737 $ — $ 3,737 Commercial paper — 12,854 12,854 — 16,570 16,570 U.S. government agency securities — 3,000 3,000 — 3,325 3,325 Corporate debt securities — 188,310 188,310 — 166,759 166,759 Total assets measured at fair value $ 4,086 $ 204,164 $ 208,250 $ 3,737 $ 189,384 $ 193,121

Cash, Cash Equivalents and Sh_2

Cash, Cash Equivalents and Short-term Investments (Tables)	12 Months Ended
	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Schedule of cash, cash equivalents and available-for-sale investments	he following tables display gross unrealized gains and losses for cash, cash equivalents and available-for-sale investments for the periods presented: December 31, 2019 (in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair value Cash and cash equivalents: Demand deposits and other cash $ 21,618 $ — $ — $ 21,618 Money market funds 4,086 — — 4,086 Total cash and cash equivalents 25,704 — — 25,704 Short-Term Investments: Commercial paper 12,861 — (7 ) 12,854 U.S. government agency securities 3,000 — — 3,000 Corporate debt securities 187,866 499 (55 ) 188,310 Total short-term investments 203,727 499 (62 ) 204,164 Total cash, cash equivalents and short-term investments $ 229,431 $ 499 $ (62 ) $ 229,868 December 31, 2018 (in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair value Cash and cash equivalents: Demand deposits and other cash $ 28,049 $ — $ — $ 28,049 Money market funds 3,737 — — 3,737 Commercial paper 2,491 — (1 ) 2,490 Corporate debt securities — — — — Total cash and cash equivalents 34,277 — (1 ) 34,276 Short-Term Investments: Commercial paper 14,091 — (11 ) 14,080 U.S. government agency securities 3,339 — (14 ) 3,325 U.S. Treasury securities 2,740 — (10 ) 2,730 Corporate debt securities 167,110 28 (379 ) 166,759 Total short-term investments 187,280 28 (414 ) 186,894 Total cash, cash equivalents and short-term investments $ 221,557 $ 28 $ (415 ) $ 221,170
Investments Classified by Contractual Maturity Date [Table Text Block]	Classification of the cash, cash equivalent and short-term investments by contractual maturity was as follows: (in thousands) One year or shorter Between 1 and 2 years Total Balances as of December 31, 2019 Cash and cash equivalents (1) $ 25,704 $ — $ 25,704 Short-term investments 113,010 91,154 204,164 Cash, cash equivalents and short-term investments $ 138,714 $ 91,154 $ 229,868 Balances as of December 31, 2018 Cash and cash equivalents (1) $ 34,276 $ — $ 34,276 Short-term investments 109,451 77,443 186,894 Cash, cash equivalents and short-term investments $ 143,727 $ 77,443 $ 221,170 (1) Includes demand deposits and other cash, money market funds and other cash equivalent securities, all with 0-90 day maturity at purchase.

Income (loss) per share (Tables

Income (loss) per share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of the computation of basic and diluted net income (loss) per share	The following table presents the calculation of basic and diluted net loss per share: Years ended December 31, (in thousands, except for share and per share amounts) 2019 2018 2017 Numerator: Net loss $ (17,980 ) $ (9,674 ) $ (10,897 ) Denominator: Weighted-average shares used to compute net loss per common share - basic and diluted 31,273 30,041 28,655 Net loss per share Basic and diluted $(0.57) $(0.32) $(0.38)
Schedule of antidilutive securities excluded from computation of earnings per share	For the years ended December 31, 2019, 2018 and 2017, the following securities were not included in the calculation of diluted shares outstanding as the effect would have been anti-dilutive: December 31, (in thousands) 2019 2018 2017 Options to purchase common stock 523 1,085 1,365 Restricted stock units 1,461 1,925 2,046

Goodwill and intangible assets

Goodwill and intangible assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	Intangible assets The fair values for acquired intangible assets were determined by management with consideration of, in part, valuations performed by independent valuation specialists. Acquisition-related intangible assets are amortized over the life of the assets on an accelerated basis that approximates the expected economic benefit of the assets. This assumption results in amortization that is higher in earlier periods of the useful life. The estimated useful lives and carrying value of acquired intangible assets are as follows: December 31, 2019 December 31, 2018 (in thousands) Weighted average useful life (years) Gross carrying amount Accumulated amortization Net carrying amount Gross carrying amount Accumulated amortization Net carrying amount Intangible assets: Customer relationships 7 to 9 $ 10,920 $ 5,819 $ 5,101 $ 10,920 $ 4,645 $ 6,275 Developed technology 3 to 7 10,050 9,803 247 10,050 7,731 2,319 Trademarks 3 to 7 1,110 1,110 — 1,110 831 279 Backlog 3 1,400 1,287 113 1,400 1,203 197 Non-compete agreements 2 to 4 460 460 — 460 460 — Intangible assets, net book value $ 23,940 $ 18,479 $ 5,461 $ 23,940 $ 14,870 $ 9,070 Amortization of intangible assets was $3.6 million , $4.5 million and $4.6 million for the years ended December 31, 2019 , 2018 and 2017 , respectively.
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Amortization of acquired intangible assets is reflected in the cost of revenues for developed technology and backlog and in operating expenses for the other intangibles. The estimated future amortization of acquired intangible assets as of December 31, 2019 was as follows: (in thousands) Future amortization 2020 $ 1,356 2021 1,130 2022 1,050 2023 1,050 2024 875 Future amortization expense $ 5,461

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2019
Balance Sheet Components [Abstract]
Inventories	Inventories December 31, (in thousands) 2019 2018 Raw materials $ 831 $ 197 Finished goods 3,745 4,153 Total inventories $ 4,576 $ 4,350
Property and Equipment	Property and equipment, net December 31, (in thousands) 2019 2018 Computer equipment and software $ 13,596 $ 10,433 Furniture, fixtures and equipment 2,430 2,246 Leasehold improvements 5,283 5,183 Manufacturing tools and equipment 2,435 2,371 Construction in process 582 520 Property and equipment, at cost 24,326 20,753 Less: Accumulated depreciation (15,665 ) (13,285 ) Property and equipment, net $ 8,661 $ 7,468 Depreciation and amortization expense for property and equipment for the years ended December 31, 2019 , 2018 and 2017 was $3.7 million , $3.2 million and $3.0 million , respectively.
Schedule of net investment in sales type leases [Table Text Block]	The Company has sales-type leases with terms of 3 to 4 years. Sales-type lease receivables are collateralized by the underlying equipment. The components of the net investment in sales-type leases are as follows: December 31, (in thousands) 2019 2018 Minimum payments to be received on sales-type leases $ 2,078 $ 2,111 Less: Unearned interest income and executory revenue portion (1,190 ) (1,387 ) Net investment in sales-type leases 888 724 Less: Current portion (452 ) (427 ) Non-current net investment in sales-type leases $ 436 $ 297 Sales-type lease activity recognized in the consolidated statement of operations are as follows: Years ended December 31, (in thousands) 2019 2018 2017 Lease revenue $ 6,394 $ 2,697 $ 2,932 Less: Cost of lease shipments (1,670 ) (212 ) (306 ) Gross profit $ 4,724 $ 2,485 $ 2,626 Interest income (expense), net on lease receivable $ (18 ) $ (6 ) $ 9 Initial direct cost incurred $ 277 $ 140 $ 167
Future Minimum Lease Payments for sales-type Leases	The minimum lease payments expected for future years under sales-type leases as of December 31, 2019 were as follows: (in thousands) Future lease payments 2020 $ 998 2021 615 2022 387 2023 78 Total $ 2,078
Accrued Liabilities	Accrued payroll and other current liabilities December 31, (in thousands) 2019 2018 Payroll and related expenses $ 6,053 $ 7,241 Accrued payables 2,674 2,115 Operating lease liabilities, current portion 2,323 — Lease financing, current portion 1,033 956 Product warranty 420 376 Customer prepayments 631 629 Sales and use tax payable 599 379 Other 1,024 1,189 Total accrued payroll and other current liabilities $ 14,757 $ 12,885
Lease, Cost [Table Text Block]	Supplemental balance sheet information related to leases was as follows: (in thousands) December 31, Other long-term assets $ 6,251 Accrued payroll and other current liabilities 2,323 Other long-term liabilities 4,866 Total operating lease liabilities $ 7,189 Other information related to leases was as follows: Year ended December 31, (in thousands) 2019 Supplemental Cash Flow Information Cash paid for amounts included in the measurement of lease liabilities $ 2,689 Right-of-use assets obtained in exchange for lease obligations $ 2,830 Weighted average remaining lease term 2.90 years Weighted average discount rate 8 %
Product Warranty Disclosure	A reconciliation of the changes in the Company’s warranty reserve for the years ended December 31, 2019 , 2018 and 2017 is as follows: Years ended December 31, (in thousands) 2019 2018 2017 Warranty balance at the beginning of the period $ 376 $ 353 $ 596 Warranty expense accrued for shipments during the period 435 468 503 Changes in estimate related to pre-existing warranties (192 ) (223 ) (450 ) Warranty settlements made (199 ) (222 ) (296 ) Total product warranty $ 420 $ 376 $ 353
Schedule of Product Warranty Liability	A reconciliation of the changes in the Company’s warranty reserve for the years ended December 31, 2019 , 2018 and 2017 is as follows: Years ended December 31, (in thousands) 2019 2018 2017 Warranty balance at the beginning of the period $ 376 $ 353 $ 596 Warranty expense accrued for shipments during the period 435 468 503 Changes in estimate related to pre-existing warranties (192 ) (223 ) (450 ) Warranty settlements made (199 ) (222 ) (296 ) Total product warranty $ 420 $ 376 $ 353

Common stock (Tables)

Common stock (Tables)	12 Months Ended
	Dec. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Reserved Shares for Issuance	At December 31, 2019 , the Company has 2,003,979 shares of common stock reserved for issuance under stock option plans.
Schedule of Stock Option Activity	The following table summarizes the combined stock option activity under the 2000 Plan, the 2006 Plan and the 2012 Plan and non-plan stock option agreements: Options outstanding Number of options Weighted average exercise price Weighted average remaining contractual term Aggregate intrinsic value (in years) (in thousands) Outstanding at December 31, 2018 797,501 $ 13.31 4.71 $ 20,767 Options granted — — Options exercised (187,174 ) 13.03 Options canceled (4,000 ) 10.41 Outstanding at December 31, 2019 606,327 $ 13.41 3.62 $ 4,566 Options vested and expected to vest as of December 31, 2019 606,327 $ 13.41 3.62 $ 4,566 Options vested and exercisable as of December 31, 2019 606,327 $ 13.41 3.62 $ 4,566
Options, Grants in Period, Wtd Avg Grant Date Fair Value	No options were granted during the years ended December 31, 2019, 2018 and 2017. Further information regarding the value of employee options vested and exercised during the years ended December 31, 2019 , 2018 and 2017 is set forth below. Years ended December 31, (in thousands) 2019 2018 2017 Intrinsic value of options exercised during period $ 3,700 $ 10,243 $ 18,603
Schedule of Valuation Assumptions for ESPP	The Company uses the Black-Scholes option-pricing model to calculate the fair value of periodic ESPP offerings on their offer date. The following assumptions were used for each respective period for the ESPP: Years ended December 31, 2019 2018 2017 Expected term (in years) 0.5 0.5 0.5 Volatility 33% - 50% 33% - 37.8% 29.0% - 32.0% Risk-free interest rate 1.59% - 2.51% 2.09% - 2.51% 0.61% - 1.39% Dividend yield 0.0% 0.0% 0.0%
Summary of the restricted stock activty	A summary of the restricted stock activity for the year ended December 31, 2019 is presented below: Restricted Stock Units Number of shares Weighted Average Grant Date Fair Value per Share Outstanding at December 31, 2018 1,807,180 $ 23.13 Granted 845,437 31.88 Vested (978,785 ) 20.89 Forfeited (123,186 ) 27.78 Outstanding at December 31, 2019 1,550,646 $ 28.94
Schedule of Share-based Comp Allocation of Period Costs	The following table presents the allocation of stock-based compensation expense: Years ended December 31, (in thousands) 2019 2018 2017 Cost of revenue $ 4,441 $ 3,614 $ 2,871 Research and development 3,955 2,976 2,122 Sales and marketing 7,014 6,560 6,563 General and administrative 8,455 7,814 6,640 Total stock-based compensation $ 23,865 $ 20,964 $ 18,196

Segments (Tables)

Segments (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Summary of the operating segments	The following table presents a summary of the operating segments: Years ended December 31, (in thousands) 2019 2018 2017 Revenue Product $ 92,561 $ 97,447 $ 91,585 Service 87,940 82,183 74,404 Total revenue 180,501 179,630 165,989 Cost of revenue Product 29,039 27,425 27,244 Service 42,363 40,318 37,683 Total cost of revenue 71,402 67,743 64,927 Gross profit Product 63,522 70,022 64,341 Service 45,577 41,865 36,721 Total gross profit 109,099 111,887 101,062 Operating expenses 123,222 118,192 111,762 (Loss) income from operations (14,123 ) (6,305 ) (10,700 ) Interest income (expense), net and other (3,837 ) (3,720 ) 562 Loss before income taxes $ (17,960 ) $ (10,025 ) $ (10,138 )
Summary of revenue by product line	The following tables present the Company’s revenue by product line, as well as revenue and long-lived assets by geographic region. Years ended December 31, (in thousands) 2019 2018 2017 Revenue Product Device $ 61,224 $ 60,130 $ 61,746 Software 31,337 37,317 29,839 Total product 92,561 97,447 91,585 Service Maintenance and support 68,846 62,267 52,342 Professional services and training 19,094 19,916 22,062 Total service 87,940 82,183 74,404 Total revenue $ 180,501 $ 179,630 $ 165,989
Schedule of revenue by geographic region	The Company’s revenue by geographic region, based on customer location, is summarized as follows: Years ended December 31, (in thousands) 2019 2018 2017 Revenue United States $ 164,827 $ 161,338 $ 148,993 International 15,674 18,292 16,996 Total revenue $ 180,501 $ 179,630 $ 165,989
Schedule of Geographic Disclosure of Long-Lived Assets	The Company’s tangible long-lived assets by geographic region, consisting of net property and equipment, are summarized as follows: December 31, (in thousands) 2019 2018 2017 Property and equipment, net United States $ 6,364 $ 6,265 $ 4,621 International 2,297 1,203 1,130 Total property and equipment, net $ 8,661 $ 7,468 $ 5,751

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Components of income (loss) before income tax	The components of loss before income taxes are as follows: Years ended December 31, (in thousands) 2019 2018 2017 United States $ (19,022 ) $ (10,852 ) $ (10,930 ) International 1,062 827 792 Total loss before income taxes $ (17,960 ) $ (10,025 ) $ (10,138 )
Components of the provision (benefit) for income taxes	The components of the provision for income taxes are as follows: Years ended December 31, (in thousands) 2019 2018 2017 Current Federal $ — $ — $ (10 ) State (25 ) 53 54 Foreign 240 368 324 215 421 368 Deferred Federal (43 ) (822 ) 311 State 7 99 119 Foreign (159 ) (49 ) (39 ) (195 ) (772 ) 391 Total income tax provision (benefit) $ 20 $ (351 ) $ 759
Reconciliation of the provision for income taxes at the statutory rate	Reconciliation of the provision for income taxes at the statutory rate to the Company’s provision for income tax is as follows: Years ended December 31, (in thousands) 2019 2018 2017 U.S. federal (tax benefit) provision at statutory rate $ (3,772 ) $ (2,105 ) $ (4,576 ) State (tax benefit) income taxes, net of federal benefit (646 ) (373 ) (437 ) Foreign income taxes at rates other than the US rate (145 ) 92 (21 ) Stock-based compensation (2,119 ) (3,503 ) (8,373 ) Change in valuation allowance 5,136 4,710 (6,023 ) Non-deductible executive compensation 2,383 2,418 1,624 Rate differential impact on Tax Cuts and Jobs Act — — 18,975 Research and development credits (1,209 ) (994 ) (602 ) Indefinite net operating losses carryforward (33 ) (1,470 ) — Other 425 874 192 Total $ 20 $ (351 ) $ 759
Deferred tax assets and liabilities	Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The following table presents the significant components of the Company’s deferred tax assets and liabilities for the periods presented: December 31, (in thousands) 2019 2018 Deferred tax assets Net operating loss carryforward $ 32,723 $ 29,798 Research and development credits 8,449 6,840 Depreciation and amortization 2,402 3,007 Reserves and accruals 9,349 9,661 Total deferred tax assets 52,923 49,306 Valuation allowance (40,436 ) (40,070 ) Net deferred tax assets 12,487 9,236 Deferred tax liabilities - convertible senior notes (5,848 ) (7,503 ) Deferred tax liabilities - other (7,097 ) (2,208 ) Net deferred tax liabilities $ (458 ) $ (475 )
Valuation allowance for DTA rollforward [Table Text Block]	The following table displays by contributing factor the changes in the valuation allowance for deferred tax assets since January 1, 2017: Years Ended December 31, (in thousands) 2019 2018 2017 Balance at the beginning of the period $ 40,070 $ 45,255 $ 42,339 Net operating loss carryforwards generated 2,925 2,509 3,050 R&D tax credit increase 1,609 1,014 1,121 Depreciation and amortization increase (605 ) 925 237 Reserves and accruals decrease (312 ) (581 ) (1,479 ) Deferred tax assets increase (3,251 ) (9,052 ) (13 ) Balance at the end of the period $ 40,436 $ 40,070 $ 45,255
Changes in the unrecognized tax benefits	The following table reflects changes in the unrecognized tax benefits since January 1, 2018: Years ended December 31, (in thousands) 2019 2018 Gross amount of unrecognized tax benefits as of the beginning of the period $ 1,931 $ 1,673 Increases related to prior year tax provisions — 7 Decreases related to prior year tax provisions (78 ) — Increases related to current year tax provisions 398 251 Gross amount of unrecognized tax benefits as of the end of the period $ 2,251 $ 1,931

Quarterly results of operatio_2

Quarterly results of operations (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following tables present certain unaudited consolidated quarterly financial information for each of the eight quarters ended December 31, 2019 . This quarterly information has been prepared on the same basis as the consolidated financial statements and includes all adjustments necessary to state fairly the information for the periods presented. (In thousands, except per share data) Quarters Ended 2019 March 31, June 30, September 30, December 31, Total revenue $ 35,309 $ 44,759 $ 50,781 $ 49,652 Gross profit $ 19,685 $ 27,016 $ 31,888 $ 30,510 Net income (loss) $ (11,735 ) $ (4,857 ) $ 298 $ (1,686 ) Net income (loss) attributable to common stockholders $ (11,735 ) $ (4,857 ) $ 298 $ (1,686 ) Net income (loss) per share attributable to common stockholders: Basic $ (0.38 ) $ (0.16 ) $ 0.01 $ (0.05 ) Diluted $ (0.38 ) $ (0.16 ) $ 0.01 $ (0.05 ) Weighted average shares used to compute net income (loss) per share attributable to common stockholders: Basic 30,800 31,242 31,459 31,579 Diluted 30,800 31,242 31,944 31,579 Quarters Ended 2018 March 31, June 30, September 30, December 31, Total revenue $ 40,242 $ 42,686 $ 47,822 $ 48,880 Gross profit $ 23,901 $ 25,651 $ 31,138 $ 31,197 Net income (loss) $ (4,770 ) $ (3,554 ) $ (249 ) $ (1,101 ) Net income (loss) attributable to common stockholders $ (4,770 ) $ (3,554 ) $ (249 ) $ (1,101 ) Net loss per share attributable to common stockholders: Basic and Diluted $ (0.24 ) $ (0.26 ) $ (0.01 ) $ (0.04 ) Weighted average shares used to compute net loss per common share: Basic and diluted 29,476 29,867 29,861 30,592

Convertible Senior Notes - Conv

Convertible Senior Notes - Convertible Notes and Options (Details) $ / shares in Units, shares in Millions	Dec. 31, 2019USD ($)$ / shares	May 31, 2018USD ($)day$ / sharesshares	Jun. 30, 2018USD ($)	Dec. 31, 2019USD ($)$ / shares	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Proceeds from issuance of convertible senior notes, net of issuance costs				$ 0	$ 138,854,000	$ 0
Net carrying amount	$ 117,178,000			117,178,000	110,540,000
Total interest expense				8,789,000	5,241,000	0
Capped Calls, initial strike price (in dollars per share) | $ / shares		$ 32.25
Capped Calls, initial cap price (in dollars per share) | $ / shares		$ 38.94
Capped Calls, number of shares covered | shares		4.5
Payments To Purchase Capped Calls		$ 8,900,000		0	8,907,000	$ 0
Convertible Debt | Convertible Senior Notes at 1.50%
Debt Instrument [Line Items]
Aggregate principal amount	143,750,000	$ 143,750,000		143,750,000	143,750,000
Stated interest rate		1.50%
Proceeds from issuance of convertible senior notes, net of issuance costs		$ 138,900,000
Unamortized debt discount	(23,880,000)			(23,880,000)	(29,846,000)
Unamortized issuance costs	(2,692,000)			(2,692,000)	(3,364,000)
Net carrying amount	117,178,000			117,178,000	110,540,000
Convertible Debt | Convertible Senior Notes At 1.50%, Option Portion
Debt Instrument [Line Items]
Aggregate principal amount		$ 18,750,000
Stated interest rate		1.50%
Convertible debt, conversion price (in dollars per share) | $ / shares		$ 32.25
Denominator in calculation of trading price		$ 1,000
Conditional cash repurchase, percent of principal		100.00%
Carrying amount of the equity component	33,350,000	$ 33,400,000		33,350,000	33,350,000
Debt discount effective interest rate			7.60%
Amortization of debt issuance costs			$ 4,900,000	673,000	395,000
Amortization of debt issuance costs, liability component			3,800,000
Amortization of debt issuance costs, equity component			$ 1,100,000
Issuance costs	(1,136,000)			(1,136,000)	(1,136,000)
Net carrying amount	32,214,000			32,214,000	32,214,000
Estimated fair value of the Notes	142,400,000			142,400,000
Denominator in closing price calculation	$ 100			$ 100
If-converted value, share price (in dollars per share) | $ / shares	$ 20.76			$ 20.76
If-converted value of the Notes	$ 92,500,000
Contractual interest expense				$ 2,150,000	1,342,000
Amortization of debt discount				5,966,000	3,504,000
Total interest expense				$ 8,789,000	$ 5,241,000
Convertible Debt | Convertible Senior Notes At 1.50%, Option Portion | Maximum
Debt Instrument [Line Items]
Convertible debt, threshold trading days | day		20
Convertible debt, threshold consecutive trading days | day		30
Percent of conversion price triggering conversion feature		130.00%
Convertible Debt | Convertible Senior Notes At 1.50%, Option Portion | Minimum
Debt Instrument [Line Items]
Convertible debt, threshold trading days | day		5
Convertible debt, threshold consecutive trading days | day		10
Percent of conversion price triggering conversion feature		98.00%

Revenue, deferred revenue, an_2

Revenue, deferred revenue, and deferred commissions - Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Other receivables	$ 6,312	$ 4,148
Deferred revenue, current	50,033	44,053
Deferred revenue, long-term	11,442	14,579
Total deferred revenue	61,475	58,632	$ 55,151
Stockholders' equity	$ 163,825	$ 162,867

Convertible Senior Notes - Capp

Convertible Senior Notes - Capped Calls (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	1 Months Ended	12 Months Ended
	May 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Capped Calls, initial strike price (in dollars per share)	$ 32.25
Capped Calls, initial cap price (in dollars per share)	$ 38.94
Capped Calls, number of shares covered	4.5
Payment for purchase of capped calls	$ (8,900)	$ 0	$ (8,907)	$ 0
Issuance costs			1,136
Convertible Debt | Convertible Senior Notes At 1.50%, Option Portion
Debt Instrument [Line Items]
Carrying amount of the equity component	$ 33,400	33,350	33,350
Carrying amount of equity component, net of capped calls		$ 23,307	$ 23,307

Revenue, deferred revenue, an_3

Revenue, deferred revenue, and deferred commissions - Consolidated Statement of Operations (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
Revenue
Total revenue	$ 49,652	$ 50,781	$ 44,759	$ 35,309	$ 48,880	$ 47,822	$ 42,686	$ 40,242	$ 180,501	$ 179,630	$ 165,989
Gross Profit	30,510	31,888	27,016	19,685	31,197	31,138	25,651	23,901	109,099	111,887	101,062
Operating expenses									123,222	118,192	111,762
Loss from Operations									(14,123)	(6,305)	(10,700)
Net loss	$ (1,686)	$ 298	$ (4,857)	$ (11,735)	$ (1,101)	$ (249)	$ (3,554)	$ (4,770)	(17,980)	(9,674)	(10,897)
Earnings Per Share, Basic and Diluted	$ (0.05)	$ 0.01	$ (0.16)	$ (0.38)
Earnings Per Share, Diluted	$ (0.05)	$ 0.01	$ (0.16)	$ (0.38)
Product
Revenue
Total revenue									92,561	97,447	91,585
Service
Revenue
Total revenue									87,940	82,183	74,404
Product Segment | Software [Member]
Revenue
Total revenue									31,337	37,317	29,839
Product Segment | Device [Member]
Revenue
Total revenue									61,224	60,130	61,746
Service Segment
Revenue
Total revenue									87,940	82,183	74,404
Service Segment | Professional Services and Training [Member]
Revenue
Total revenue									19,094	19,916	22,062
Service Segment | Maintenance and Support [Member]
Revenue
Total revenue									$ 68,846	$ 62,267	$ 52,342

The Company and Summary of Si_4

The Company and Summary of Significant Accounting Policies Narrative (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Sale of Stock [Line Items]
Revenue from Related Parties		$ 1,300	$ 400	$ 400
Accumulated deficit		(150,326)	(132,346)
Cash, Cash Equivalents, and Short-term Investments		229,900
Capitalized Computer Software, Additions		600	700	300
Impairment of Intangibles (Excl. Goodwill)		0	0	0
Goodwill, Impairment Loss		$ 0	0	$ 0
No of operating segments		2
Deferred Tax Assets, Valuation Allowance		$ 40,436	$ 40,070		$ 45,255	$ 42,339
Maximum
Sale of Stock [Line Items]
Product Liability, Warranty Period		3 years
Minimum
Sale of Stock [Line Items]
Product Liability, Warranty Period		1 year
Restricted stock units
Sale of Stock [Line Items]
Vesting percentage on 1st anniversary of grant (percent)		33.33%
Vesting percentage on 2nd anniversary of grant (percent)		33.33%
Vesting percentage on 3rd anniversary of grant (percent)		33.34%
Property and Equipment, excluding LHI and major ERP [Member]
Sale of Stock [Line Items]
Property, Plant and Equipment, Useful Life		3 years
Not major ERP implementation [Member] | Software and Software Development Costs [Member]
Sale of Stock [Line Items]
Property, Plant and Equipment, Useful Life		3 years
Major ERP implementation [Member] | Software and Software Development Costs [Member]
Sale of Stock [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Accounts Receivable [Member]
Sale of Stock [Line Items]
Concentration Risk, Percentage		19.30%	26.40%

Revenue, deferred revenue, an_4

Revenue, deferred revenue, and deferred commissions - Cash Flows From Operating Activities (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
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net loss	$ (1,686)	$ 298	$ (4,857)	$ (11,735)	$ (1,101)	$ (249)	$ (3,554)	$ (4,770)	$ (17,980)	$ (9,674)	$ (10,897)
Other receivables									(2,064)	(2,810)	(120)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Deferred commissions									(174)	(2)	121
Deferred revenue									$ 2,843	$ 3,482	$ 5,434

The Company and Summary of Si_5

The Company and Summary of Significant Accounting Policies Sales type lease data (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
sales type capital leases transfered to banks	$ 3,500	$ 400
Sales-type Lease, Lease Income	300
financing liability for future executory services on transfered leases	1,700	300
Net Investment in Lease	$ 888	$ 724

Revenue, deferred revenue, an_5

Revenue, deferred revenue, and deferred commissions - Disaggregation of 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
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	$ 49,652	$ 50,781	$ 44,759	$ 35,309	$ 48,880	$ 47,822	$ 42,686	$ 40,242	$ 180,501	$ 179,630	$ 165,989
Product
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue									92,561	97,447	91,585
Product Segment | Software [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue									31,337	37,317	29,839
Product Segment | Device [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue									61,224	60,130	61,746
Service Segment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue									87,940	82,183	74,404
Service Segment | Maintenance and Support [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue									68,846	62,267	52,342
Service Segment | Professional Services and Training [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue									19,094	19,916	22,062
United States
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue									164,827	161,338	148,993
International
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue									$ 15,674	$ 18,292	$ 16,996

Revenue, deferred revenue, an_6

Revenue, deferred revenue, and deferred commissions - Significant Changes in Deferred Commissions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Change in Contract with Customer, Asset [Roll Forward]
Beginning balance	$ 10,303	$ 10,301
Additions	7,761	8,327
Commissions Recognized	(7,587)	(8,325)
Ending balance	$ 10,477	$ 10,303

Revenue, deferred revenue, an_7

Revenue, deferred revenue, and deferred commissions - Significant Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Change in Contract with Customer, Liability [Roll Forward]
Beginning balance	$ 58,632	$ 55,151
Additions	82,042	77,969
Revenue Recognized	(79,199)	(74,488)
Ending balance	$ 61,475	$ 58,632

The Company and Summary of Si_6

The Company and Summary of Significant Accounting Policies The company and significant accounting policies - Deferred Costs of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Contract with Customer, Payment Terms	30 days
Contract with Customer, Asset, Gross	$ 4.3	$ 2.4

Revenue, deferred revenue, an_8

Revenue, deferred revenue, and deferred commissions - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Payment terms on invoiced amounts	30 days
Contract assets	$ 4,300	$ 2,400
Deferred commissions	$ 10,477	10,303	$ 10,301
Percentage of deferred commissions to be recognized as commission expense in the next 12 months	49.00%
Revenue recognized pertaining to amounts deferred as of December 31, 2017	$ 48,600	$ 42,600
Deferred revenue and backlog	$ 123,500
Percentage of deferred revenue to be recognized over the next 12 months	66.00%

The Company and Summary of Si_7

The Company and Summary of Significant Accounting Policies Background (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2015
Valuation Allowance [Abstract]
Accumulated deficit	$ (150,326)	$ (132,346)
Deferred Tax Assets, Valuation Allowance	$ 40,436	$ 40,070	$ 45,255	$ 42,339

The Company and Summary of Si_8

The Company and Summary of Significant Accounting Policies Recently adopted accounting pronouncements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term assets	$ 6,251
Total	$ 7,189
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term assets		$ 5,100
Total		$ 6,700

The Company and Summary of Si_9

The Company and Summary of Significant Accounting Policies - Revenue from contract with customers (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
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	$ 49,652	$ 50,781	$ 44,759	$ 35,309	$ 48,880	$ 47,822	$ 42,686	$ 40,242	$ 180,501	$ 179,630	$ 165,989
Prepaid expenses and other current assets	5,149				4,691				5,149	4,691
Gross Profit	30,510	31,888	27,016	19,685	31,197	31,138	25,651	23,901	109,099	111,887	101,062
Operating Expenses									123,222	118,192	111,762
Loss from Operations									(14,123)	(6,305)	(10,700)
Net loss	(1,686)	$ 298	$ (4,857)	$ (11,735)	$ (1,101)	$ (249)	$ (3,554)	$ (4,770)	$ (17,980)	$ (9,674)	$ (10,897)
Basic and diluted					$ (0.04)	$ (0.01)	$ (0.26)	$ (0.24)	$ (0.57)	$ (0.32)	$ (0.38)
Other receivables	6,312				$ 4,148				$ 6,312	$ 4,148
Deferred revenue, current	50,033				44,053				50,033	44,053
Deferred revenue, long-term	11,442				14,579				11,442	14,579
Total deferred revenue	61,475				58,632				61,475	58,632	$ 55,151
Stockholders' equity	$ 163,825				$ 162,867				$ 163,825	162,867
As Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Basic and diluted									$ (0.57)
Product
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue									$ 92,561	97,447	91,585
Service
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue									$ 87,940	$ 82,183	$ 74,404

Fair value of financial instr_3

Fair value of financial instruments Schedule of assets and liabilities measured at fair value on a recurring basis, by level (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets, Fair Value Disclosure [Abstract]
Fair value	$ 25,704	$ 34,276
Fair value	204,164	186,894
U.S. government agency securities
Assets, Fair Value Disclosure [Abstract]
Fair value	3,000	3,325
U.S. Treasury securities
Assets, Fair Value Disclosure [Abstract]
Fair value		2,730
Corporate debt securities
Assets, Fair Value Disclosure [Abstract]
Fair value	188,310	166,759
Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Total assets measured at fair value	208,250	193,121
Fair Value, Measurements, Recurring | Level 1
Assets, Fair Value Disclosure [Abstract]
Total assets measured at fair value	4,086	3,737
Fair Value, Measurements, Recurring | Level 2
Assets, Fair Value Disclosure [Abstract]
Total assets measured at fair value	204,164	189,384
Fair Value, Measurements, Recurring | U.S. government agency securities
Assets, Fair Value Disclosure [Abstract]
Fair value	3,000	3,325
Fair Value, Measurements, Recurring | U.S. government agency securities | Level 1
Assets, Fair Value Disclosure [Abstract]
Fair value	0	0
Fair Value, Measurements, Recurring | U.S. government agency securities | Level 2
Assets, Fair Value Disclosure [Abstract]
Fair value	3,000	3,325
Fair Value, Measurements, Recurring | Corporate debt securities
Assets, Fair Value Disclosure [Abstract]
Fair value	188,310	166,759
Fair Value, Measurements, Recurring | Corporate debt securities | Level 1
Assets, Fair Value Disclosure [Abstract]
Fair value	0	0
Fair Value, Measurements, Recurring | Corporate debt securities | Level 2
Assets, Fair Value Disclosure [Abstract]
Fair value	188,310	166,759
Fair Value, Measurements, Recurring | Money Market Funds [Member]
Assets, Fair Value Disclosure [Abstract]
Fair value	4,086	3,737
Fair Value, Measurements, Recurring | Money Market Funds [Member] | Level 1
Assets, Fair Value Disclosure [Abstract]
Fair value	4,086	3,737
Fair Value, Measurements, Recurring | Money Market Funds [Member] | Level 2
Assets, Fair Value Disclosure [Abstract]
Fair value	0	0
Fair Value, Measurements, Recurring | Commercial paper
Assets, Fair Value Disclosure [Abstract]
Fair value	12,854	16,570
Fair Value, Measurements, Recurring | Commercial paper | Level 1
Assets, Fair Value Disclosure [Abstract]
Fair value	0	0
Fair Value, Measurements, Recurring | Commercial paper | Level 2
Assets, Fair Value Disclosure [Abstract]
Fair value	$ 12,854	$ 16,570

Cash, Cash Equivalents and Sh_3

Cash, Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Cash and cash equivalents:
Amortized Cost	$ 25,704	$ 34,277
Unrealized Gains	0	0
Unrealized Losses	0	(1)
Fair value	25,704	34,276
Short-Term Investments:
Amortized Cost	203,727	187,280
Unrealized Gains	499	28
Unrealized Losses	(62)	(414)
Fair value	204,164	186,894
Cash, Cash Equivalents, and Short-term Investments:
Amortized Cost	229,431	221,557
Cash, cash equivalents and short-term investments	229,868	221,170
Cash, Cash Equivalents And Short Term Investments, Accumulated Gross Unrealized Gain	499	28
Cash, Cash Equivalents And Short Term Investments, Accumulated Gross Unrealized Loss	62	415
U.S. Treasury securities
Short-Term Investments:
Amortized Cost		2,740
Unrealized Gains		0
Unrealized Losses		(10)
Fair value		2,730
U.S. government agency securities
Short-Term Investments:
Amortized Cost	3,000	3,339
Unrealized Gains	0	0
Unrealized Losses	0	(14)
Fair value	3,000	3,325
Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Short-Term Investments:
Amortized Cost	12,861	14,091
Unrealized Gains	0	0
Unrealized Losses	(7)	(11)
Fair value	12,854	14,080
Corporate debt securities
Short-Term Investments:
Amortized Cost	187,866	167,110
Unrealized Gains	499	28
Unrealized Losses	(55)	(379)
Fair value	188,310	166,759
Demand deposis and other cash
Cash and cash equivalents:
Amortized Cost	21,618	28,049
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair value	21,618	28,049
Money Market Funds [Member]
Cash and cash equivalents:
Amortized Cost	4,086	3,737
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair value	$ 4,086	3,737
Commercial paper
Cash and cash equivalents:
Amortized Cost		2,491
Unrealized Gains		0
Unrealized Losses		(1)
Fair value		2,490
Corporate debt securities
Cash and cash equivalents:
Amortized Cost		0
Unrealized Gains		0
Unrealized Losses		0
Fair value		$ 0

Cash, Cash Equivalents and Sh_4

Cash, Cash Equivalents and Short-term Investments Classification by contractual maturity of cash, cash equivalents and short-term investments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Fair value	$ 25,704	$ 34,276
Fair value	204,164	186,894
Cash, cash equivalents and short-term investments	229,868	221,170
Maturity up to one year [Member]
Debt Securities, Available-for-sale [Line Items]
Fair value	25,704	34,276
Fair value	113,010	109,451
Cash, cash equivalents and short-term investments	138,714	143,727
maturity between 1 and 2 years [Member]
Debt Securities, Available-for-sale [Line Items]
Fair value	0	0
Fair value	91,154	77,443
Cash, cash equivalents and short-term investments	$ 91,154	$ 77,443

Income (loss) per share Schedul

Income (loss) per share Schedule of the computation of basic and diluted net income (loss) per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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:
Net loss	$ (1,686)	$ 298	$ (4,857)	$ (11,735)	$ (1,101)	$ (249)	$ (3,554)	$ (4,770)	$ (17,980)	$ (9,674)	$ (10,897)
Net (loss) income attributable to common stockholders	$ (1,686)	$ 298	$ (4,857)	$ (11,735)	$ (1,101)	$ (249)	$ (3,554)	$ (4,770)
Net Income (Loss) Available to Common Stockholders, Diluted									$ (17,980)	$ (9,674)	$ (10,897)
Denominator:
Weighted-average shares used to compute net loss per common share - basic and diluted	31,579	31,459	31,242	30,800					31,273	30,041	28,655
Weighted average shares used to compute diluted income (loss) per common share	31,579	31,944	31,242	30,800					31,273	30,041	28,655
Net loss per share
Basic and diluted					$ (0.04)	$ (0.01)	$ (0.26)	$ (0.24)	$ (0.57)	$ (0.32)	$ (0.38)

Income (loss) per share Sched_2

Income (loss) per share Schedule of antidilutive securities excluded from computation of earnings per share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee stock options, including ESPP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	523	1,085
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			1,365
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,461	1,925	2,046

Goodwill and intangible asset_2

Goodwill and intangible assets Schedule of Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ 18,479	$ 14,870
Finite-Lived Intangible Assets, Net	5,461
Intangible Assets, Gross (Excluding Goodwill)	23,940	23,940
Intangible assets, net	5,461	9,070
Goodwill [Abstract]
Goodwill	49,246	49,246
Impairment and Amortization [Abstract]
Goodwill, Impairment Loss	0	0	$ 0
Impairment of Intangibles (Excl. Goodwill)	0	0	0
Amortization expense	3,600	4,500	$ 4,600
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	10,920	10,920
Accumulated amortization	5,819	4,645
Finite-Lived Intangible Assets, Net	5,101	6,275
Technology-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	10,050	10,050
Accumulated amortization	9,803	7,731
Finite-Lived Intangible Assets, Net	247	2,319
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,110	1,110
Accumulated amortization	1,110	831
Finite-Lived Intangible Assets, Net	0	279
Backlog
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,400	1,400
Accumulated amortization	1,287	1,203
Finite-Lived Intangible Assets, Net	113	197
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	460	460
Accumulated amortization	460	460
Finite-Lived Intangible Assets, Net	$ 0	$ 0
Minimum [Member] | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	7 years
Minimum [Member] | Technology-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	3 years
Minimum [Member] | Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	3 years
Minimum [Member] | Backlog
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	3 years
Minimum [Member] | Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	2 years
Maximum [Member] | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	9 years
Maximum [Member] | Technology-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	7 years
Maximum [Member] | Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	7 years
Maximum [Member] | Backlog
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	3 years
Maximum [Member] | Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Weighted average useful life (years)	4 years
Product Segment
Goodwill [Abstract]
Goodwill	$ 41,200
Service Segment
Goodwill [Abstract]
Goodwill	$ 8,000

Goodwill and intangible asset_3

Goodwill and intangible assets Future amortization schedule (Details) $ in Thousands	Dec. 31, 2019USD ($)
Goodwill and intangible assets [Abstract]
2020	$ 1,356
2021	1,130
2022	1,050
2023	1,050
2024	875
Finite-Lived Intangible Assets, Net	$ 5,461

Balance Sheet Components Invent

Balance Sheet Components Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory, Net [Abstract]
Raw materials	$ 831	$ 197
Finished goods	3,745	4,153
Total inventories	$ 4,576	$ 4,350

Balance Sheet Components Proper

Balance Sheet Components Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	$ 24,326	$ 20,753
Less: Accumulated depreciation	(15,665)	(13,285)
Property and equipment, net	8,661	7,468	$ 5,751
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	13,596	10,433
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	2,430	2,246
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	5,283	5,183
Manufacturing tools and equipment
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	2,435	2,371
Construction in process
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	$ 582	$ 520

Balance Sheet Components Deprec

Balance Sheet Components Depreciation, depletion, amortization (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property-Equipment Deepreciation and amortization [Abstract]
Depreciation and amortization	$ 3.7	$ 3.2	$ 3

Balance Sheet Components Balanc

Balance Sheet Components Balance sheet components - investment in sales type leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investment in Sales Type Leases
Minimum payments to be received on sales-type leases	$ 2,078	$ 2,111
Less: Unearned interest income and executory revenue portion	(1,190)	(1,387)
Net investment in sales-type leases	888	724
Less: Current portion	(452)	(427)
Non-current net investment in sales-type leases	436	297
Lease revenue	6,394	2,697	$ 2,932
Less: Cost of lease shipments	(1,670)	(212)	(306)
Gross profit	4,724	2,485	2,626
Interest income (expense), net on lease receivable	18	6	9
Initial direct cost incurred	$ 277	$ 140	$ 167
Minimum
Investment in Sales Type Leases
Term of Operating Lease Contract	3 years
Maximum
Investment in Sales Type Leases
Term of Operating Lease Contract	4 years

Balance Sheet Components Bala_2

Balance Sheet Components Balance sheet components - sales type lease Future Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Components [Abstract]
2020	$ 998
2021	615
2022	387
2023	78
Total	$ 2,078	$ 2,111

Balance Sheet Components Accrue

Balance Sheet Components Accrued Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance Sheet Components [Abstract]
2022	$ 1,385
Product Warranty Accrual, Payments	199	$ 222	$ 296
Accrued Liabilities, Current [Abstract]
Payroll and related expenses	6,053	7,241
Accrued payables	2,674	2,115
Operating lease liabilities, current portion	2,323	0
Lease financing, current portion	1,033	956
Product warranty	420	376
Customer Refund Liability, Current	631	629
Sales and use tax payable	599	379
Other	1,024	1,189
Total accrued payroll and other current liabilities	$ 14,757	$ 12,885

Balance Sheet Components Bala_3

Balance Sheet Components Balance sheet components Product Warranties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
movement in std product warranty liability [Roll Forward]
Warranty balance at the beginning of the period	$ 376		$ 596
Warranty expense accrued for shipments during the period	435	$ 468	503
Changes in estimate related to pre-existing warranties	(192)	(223)	(450)
Warranty settlements made	(199)	(222)	(296)
Current portion of warranty balance at the end of the period		376
Product Warranty Accrual	$ 420	$ 376	$ 353

Balance Sheet Components Leases

Balance Sheet Components Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance Sheet Components [Abstract]
Operating Lease, Cost	$ 2,700	$ 2,700	$ 2,600
Other long-term assets	6,251
Accrued payroll and other current liabilities	2,323	$ 0
Other long-term liabilities	4,866
Total	$ 7,189

Balance Sheet Components Other

Balance Sheet Components Other Lease Components (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Balance Sheet Components [Abstract]
Cash paid for amounts included in the measurement of lease liabilities	$ 2,689
Right-of-use assets obtained in exchange for lease obligations	$ 2,830
Weighted average remaining lease term	2 years 10 months 24 days
Weighted average discount rate	8.00%

Balance Sheet Components Lease

Balance Sheet Components Lease Maturities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance Sheet Components [Abstract]
2020	$ 2,852
2021	3,043
2022	1,385
2023	442
2024	353
Total maturities of lease liabilities	8,075
Less imputed interest	(886)
Total	7,189
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019		$ 2,224
2020		2,077
2021		1,835
2022		612
2023		35
Operating Lease, Cost	$ 2,700	2,700	$ 2,600
Total maturities of lease liabilities		$ 6,783

Commitments Schedule of Future

Commitments Schedule of Future Minimum Rental Payments for Operating Leases (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Inventories
Unrecorded Unconditional Purchase Obligation [Line Items]
Non-cancelable purchase commitment with a third party manufacturer to purchase inventory	$ 9.7	$ 11.1

Common stock (Details)

Common stock (Details) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value	$ 0.0003	$ 0.0003

Common stock (Reserved shares f

Common stock (Reserved shares for issuance of common stock) (Details)	Dec. 31, 2019shares
Options to purchase common stock
Class of Stock [Line Items]
Common stock (in shares)	2,003,979

Common stock (Incentive stock o

Common stock (Incentive stock option plans) (Details)	Dec. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of equity incentive plans	4

Common stock (Options outstandi

Common stock (Options outstanding) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Options vested and expected to vest (Number of options)	606,327
Options vested and expected to vest (Wtd avg exercise price)	$ 13.41
Options vested and expected to vest (Wtd avg remaining contractual term)	3 years 7 months 13 days
Options vested and expected to vest (Aggregate intrinsic value)	$ 4,566
Options vested and exercisable (Number of options)	606,327
Options vested and exercisable (Wtd avg exercise price)	$ 13.41
Options vested and exercisable (Wtd avg remaining contractual term)	3 years 7 months 13 days
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Options, Outstanding, Beginning balance	797,501
Options granted	0
Options exercised	(187,174)
Number of Options, Outstanding, Ending balance	606,327	797,501
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 13.31
Wtd Avg Remaining Contractual Term, Options Outstanding	3 years 7 months 13 days	4 years 8 months 15 days
Options granted	$ 0
Options exercised	13.03
Weighted Average Exercise Price, Outstanding, Ending balance	$ 13.41	$ 13.31
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period	4,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 10.41
Share-based Compensation Arrangement by Share-based Payment Award, Options, Aggregate Intrinsic Value [Abstract]
Aggregate Intrinsic Value, Options Outstanding	$ 4,566	$ 20,767

Common stock (Fair value option

Common stock (Fair value option pricing model) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Options - intrinsic value and grant date fair value [Abstract]
Options vested and exercisable (Aggregate intrinsic value)	$ 4,566

Common stock (Employee options

Common stock (Employee options vested and exercised) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options, Exercises in Period, Total Intrinsic Value	$ 3,700	$ 10,243	$ 18,603

Common stock (Restricted stock

Common stock (Restricted stock awards and restricted stock units) (Details) - Restricted Stock Units (RSUs) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 30.2
Outstanding, Number of Shares	1,550,646	1,807,180
Outstanding, Wtd Ag Grant Date Fair Value	$ 28.94	$ 23.13
Vesting percentage on 1st anniversary of grant (percent)	33.33%
Vesting percentage on 2nd anniversary of grant (percent)	33.33%
Vesting percentage on 3rd anniversary of grant (percent)	33.34%

Common stock (Summary of restri

Common stock (Summary of restricted stock activity) (Details) - Restricted Stock Units - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period (in years)	1 year 7 months 24 days
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 30.2
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, Number of Shares	1,807,180
Granted, Number of Shares	845,437
Vested, Number of Shares	978,785
Forfeited, Number of Shares	123,186
Outstanding, Number of Shares	1,550,646
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Granted, Wtd Avg Grant Date Fair Value	$ 31.88
Vested, Wtd Avg Grant Date Fair Value	20.89
Forfeitured, Wtd Avg Grant Date Fair Value	27.78
Outstanding, Wtd Ag Grant Date Fair Value	$ 28.94	$ 23.13

Common stock (Granted employee

Common stock (Granted employee and nonemployee options) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation expense	$ 23,865	$ 20,964	$ 18,196

Common stock (Recognized expens

Common stock (Recognized expenses nonemployee stock-based compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 23,865	$ 20,964	$ 18,196

Common stock (Common stock) Sha

Common stock (Common stock) Share-based compensation allocated to expense captions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 23,865	$ 20,964	$ 18,196
Cost of Sales [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	4,441	3,614	2,871
Research and Development Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	3,955	2,976	2,122
Selling and Marketing Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	7,014	6,560	6,563
General and Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 8,455	$ 7,814	$ 6,640

Common stock Common Stock (ESPP

Common stock Common Stock (ESPP B-S-M option pricing model assumptions) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
ESPP plan details [Abstract]
Stock Shares Issued During Period, ESPP	155,373	157,426
Two Thousand Twelve Employee Stcok Purchase Plan [Member] | Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%
ESPP plan details [Abstract]
ESPP-Maximum Annual Purchase by Employee, Percent	15.00%
Share-based Compensation Arrangements by Share-based Payment Award, Offering Period, Subsequent Offers	6 months
ESPP-Discount of market Price	85.00%
Share-based Comp, Per Share Wtd Avg Price of Shares Purchased	$ 22.35	$ 20.77
Common stock (in shares) reserved for ESPP	873,011
Two Thousand Twelve Employee Stcok Purchase Plan [Member] | Employee Stock [Member] | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (years)	6 months	6 months	6 months
Expected Volatility Rate	33.00%	33.00%	29.00%
Risk-free interest rate	1.59%	2.09%	0.61%
Two Thousand Twelve Employee Stcok Purchase Plan [Member] | Employee Stock [Member] | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (years)	6 months	6 months	6 months
Expected Volatility Rate	50.00%	37.80%	32.00%
Risk-free interest rate	2.51%	2.51%	1.39%

Segments Summary of the operati

Segments Summary of the operating segments (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments									2
Revenue
Total revenue	$ 49,652	$ 50,781	$ 44,759	$ 35,309	$ 48,880	$ 47,822	$ 42,686	$ 40,242	$ 180,501	$ 179,630	$ 165,989
Cost of revenue
Total cost of revenue									71,402	67,743	64,927
Gross Profit [Abstract]
Gross Profit, Goods									63,522	70,022	64,341
Gross Profit, Services									45,577	41,865	36,721
Gross profit	$ 30,510	$ 31,888	$ 27,016	$ 19,685	$ 31,197	$ 31,138	$ 25,651	$ 23,901	109,099	111,887	101,062
Operating expenses									123,222	118,192	111,762
Interest income (expense) and other											562
Loss before income taxes									$ (17,960)	$ (10,025)	$ (10,138)

Segments Summary of revenue by

Segments Summary of revenue by product line (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
Revenue from External Customer [Line Items]
Total revenue	$ 49,652	$ 50,781	$ 44,759	$ 35,309	$ 48,880	$ 47,822	$ 42,686	$ 40,242	$ 180,501	$ 179,630	$ 165,989
Product
Revenue from External Customer [Line Items]
Total revenue									92,561	97,447	91,585
Product Segment | Device [Member]
Revenue from External Customer [Line Items]
Total revenue									61,224	60,130	61,746
Product Segment | Software [Member]
Revenue from External Customer [Line Items]
Total revenue									31,337	37,317	29,839
Service Segment
Revenue from External Customer [Line Items]
Total revenue									87,940	82,183	74,404
Service Segment | Maintenance and Support [Member]
Revenue from External Customer [Line Items]
Total revenue									68,846	62,267	52,342
Service Segment | Professional Services and Training [Member]
Revenue from External Customer [Line Items]
Total revenue									$ 19,094	$ 19,916	$ 22,062

Segments Schedule of revenue by

Segments Schedule of revenue by geographic region (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	Dec. 31, 2016
Geographic Areas, Revenues from External Customers [Abstract]
Total revenue	$ 49,652	$ 50,781	$ 44,759	$ 35,309	$ 48,880	$ 47,822	$ 42,686	$ 40,242	$ 180,501	$ 179,630	$ 165,989
Geographic Areas, Long-Lived Assets [Abstract]
Property and equipment, net	8,661				7,468				8,661	7,468		$ 5,751
United States
Geographic Areas, Revenues from External Customers [Abstract]
Total revenue									164,827	161,338	148,993
Geographic Areas, Long-Lived Assets [Abstract]
Property and equipment, net	6,364				6,265				6,364	6,265		4,621
International
Geographic Areas, Revenues from External Customers [Abstract]
Total revenue									15,674	18,292	$ 16,996
Geographic Areas, Long-Lived Assets [Abstract]
Property and equipment, net	$ 2,297				$ 1,203				$ 2,297	$ 1,203		$ 1,130

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
United States	$ (19,022)	$ (10,852)	$ (10,930)
International	1,062	827	792
Total loss before income taxes	$ (17,960)	$ (10,025)	$ (10,138)

Income Taxes (Components of the

Income Taxes (Components of the provision (benefit) for income taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current
Federal	$ 0	$ 0	$ (10)
State	(25)	53	54
Foreign	240	368	324
Current Income Tax Expense (Benefit)	215	421	368
Deferred
Federal	(43)	(822)	311
State	7	99	119
Foreign	(159)	(49)	(39)
Deferred Income Tax Expense (Benefit)	(195)	(772)	391
Total income tax provision (benefit)	$ 20	$ (351)	$ 759

Income Taxes (Reconciliation of

Income Taxes (Reconciliation of the provision for income taxes at the statutory rate to the company's provision for income tax) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S. federal (tax benefit) provision at statutory rate	$ (3,772)	$ (2,105)	$ (4,576)
State (tax benefit) income taxes, net of federal benefit	(646)	(373)	(437)
Foreign income taxes at rates other than the US rate	(145)	92	(21)
Stock-based compensation	(2,119)	(3,503)	(8,373)
Change in valuation allowance	5,136	4,710	(6,023)
Non-deductible executive compensation	2,383	2,418	1,624
Rate differential impact on Tax Cuts and Jobs Act	0	0	18,975
Research and development credits	(1,209)	(994)	(602)
Indefinite net operating losses carryforward	(33)
Other	425	874	192
Total income tax provision (benefit)	$ 20	$ (351)	$ 759
Effective Income Tax Rate, Percent [Abstract]
Effective tax rate	0.10%	(3.50%)	7.50%

Income Taxes (Deferred tax asse

Income Taxes (Deferred tax assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Net operating loss carryforward	$ 32,723	$ 29,798
Research and development credits	8,449	6,840
Deferred Tax Assets, Property, Plant and Equipment	2,402	3,007
Reserves and accruals	9,349	9,661
Total deferred tax assets	52,923	49,306
Valuation allowance	(40,436)	(40,070)	$ (45,255)	$ (42,339)
Net deferred tax assets	12,487	9,236
Deferred tax liabilities - convertible senior notes	(5,848)	(7,503)
Deferred tax liabilities - other	(7,097)	(2,208)
Net deferred tax liabilities	(458)	(475)
Deferred tax assets (increase) decrease	$ (400)	$ 5,200

Income Taxes (Tax carry forward

Income Taxes (Tax carry forwards) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Tax Credit Carryforward [Line Items]
Research and development credits	$ 8,449	$ 6,840
Tax Credit Carryforward, Amount	500
Deferred tax assets decrease	(400)	$ 5,200
Tax Credit Carryforward, Limitations on Use	600
Federal | Federal R&D tax credits carryforwards [Member]
Tax Credit Carryforward [Line Items]
Research and development credits	5,300
State | State R&D tax credits carryforwards [Member]
Tax Credit Carryforward [Line Items]
Research and development credits	$ 5,900

Income Taxes Income Taxes (Oper

Income Taxes Income Taxes (Operating Loss Carryovers) (Details) $ in Millions	Dec. 31, 2019USD ($)
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Limitations on Use	$ 11.5
Operating Loss Carryforwards	5.3
Federal
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	137
State
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 69

Income Taxes (income Taxes) DTA

Income Taxes (income Taxes) DTA Valuation Allowance Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes (DTA Valuation Allowance Rollforward) [Abstract]
Balance at the beginning of the period	$ 40,070		$ 45,255
Net operating loss carryforwards generated	2,925	$ 2,509	3,050
R&D tax credit increase	1,609	1,014	1,121
Depreciation and amortization increase	(605)	925	237
Reserves and accruals decrease	(312)	(581)	(1,479)
Deferred tax assets increase	(3,251)	(9,052)	$ (13)
Balance at the end of the period	$ 40,436	$ 40,070

Income Taxes (Changes in unreco

Income Taxes (Changes in unrecognized tax benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	$ 0	$ 7
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Gross amount of unrecognized tax benefits as of the beginning of the period	1,931	1,673
Decreases related to prior year tax provisions	(78)	0
Increases related to current year tax provisions	398	251
Gross amount of unrecognized tax benefits as of the end of the period	$ 2,251	$ 1,931

Quarterly results of operatio_3

Quarterly results of operations (unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Quarterly Financial Information Disclosure [Abstract]
Total revenue	$ 49,652	$ 50,781	$ 44,759	$ 35,309	$ 48,880	$ 47,822	$ 42,686	$ 40,242	$ 180,501	$ 179,630	$ 165,989
Gross Profit	30,510	31,888	27,016	19,685	31,197	31,138	25,651	23,901	109,099	111,887	101,062
Net loss	(1,686)	298	(4,857)	(11,735)	(1,101)	(249)	(3,554)	(4,770)	$ (17,980)	$ (9,674)	$ (10,897)
Net Income (Loss) Available to Common Stockholders, Basic	$ (1,686)	$ 298	$ (4,857)	$ (11,735)	$ (1,101)	$ (249)	$ (3,554)	$ (4,770)
Earnings Per Share, Basic	$ (0.05)	$ 0.01	$ (0.16)	$ (0.38)
Basic and diluted					$ (0.04)	$ (0.01)	$ (0.26)	$ (0.24)	$ (0.57)	$ (0.32)	$ (0.38)
Earnings Per Share, Diluted	$ (0.05)	$ 0.01	$ (0.16)	$ (0.38)
Basic	31,579	31,459	31,242	30,800					31,273	30,041	28,655
Weighted Average Number of Shares Outstanding, Basic					30,592	29,861	29,867	29,476
Diluted	31,579	31,944	31,242	30,800					31,273	30,041	28,655