Vocera Communications (VCRA) 10-K 5 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Mar. 01, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	VOCERA COMMUNICATIONS, INC.
Entity Central Index Key	1,129,260
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Common Stock, Shares Outstanding		29,524,347
Entity Public Float			$ 631

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 28,726	$ 35,033
Short-term investments	52,507	39,033
Accounts receivable, net	35,105	24,142
Other receivables	1,170	1,211
Inventories	2,815	4,556
Prepaid expenses and other current assets	3,957	3,364
Total current assets	124,280	107,339
Property and equipment, net	5,751	5,894
Intangible assets, net	13,567	18,200
Goodwill	49,246	49,246
Other long-term assets	1,667	1,394
Total assets	194,511	182,073
Current liabilities
Accounts payable	2,678	3,231
Accrued payroll and other current liabilities	14,689	15,896
Deferred revenue, current	47,276	43,845
Total current liabilities	64,643	62,972
Deferred revenue, long-term	16,438	11,155
Other long-term liabilities	4,455	4,505
Total liabilities	85,536	78,632
Commitments and contingencies (Note 7)
Stockholders' equity
Preferred stock, $0.0003 par value - 5,000,000 shares authorized as of December 31, 2017 and December 31, 2016; zero shares issued and outstanding	0	0
Common stock, $0.0003 par value - 100,000,000 shares authorized as of December 31, 2017 and December 31, 2016; 29,412,116 and 27,568,103 shares issued and outstanding as of December 31, 2017 and December 31, 2016, respectively	9	8
Additional paid-in capital	250,854	230,605
Accumulated other comprehensive loss	(191)	(69)
Accumulated deficit	(141,697)	(127,103)
Total stockholders’ equity	108,975	103,441
Total liabilities and stockholders’ equity	$ 194,511	$ 182,073

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Paranthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
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	29,412,116	27,568,103
Common stock, shares outstanding	29,412,116	27,568,103
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, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue
Product	$ 88,865	$ 70,667	$ 55,716
Service	73,683	57,029	48,370
Total revenue	162,548	127,696	104,086
Cost of Revenue [Abstract]
Product	27,244	22,788	19,666
Service	37,683	26,287	19,844
Total cost of revenue	64,927	49,075	39,510
Gross profit	97,621	78,621	64,576
Operating expenses
Research and development	27,685	18,266	16,990
Sales and marketing	59,986	52,811	47,647
General and administrative	23,970	24,499	16,734
Total operating expenses	111,641	95,576	81,371
Loss from operations	(14,020)	(16,955)	(16,795)
Interest income	604	684	509
Other expense, net	(42)	(467)	(347)
Loss before income taxes	(13,458)	(16,738)	(16,633)
Provision for income taxes	(759)	(529)	(473)
Net loss	$ (14,217)	$ (17,267)	$ (17,106)
Net loss per share:
Basic and diluted	$ (0.50)	$ (0.64)	$ (0.66)
Weighted average shares used to compute net loss per share:
Basic	28,655	26,859	25,971
Diluted	28,655	26,859	25,971

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net loss	$ (14,217)	$ (17,267)	$ (17,106)
Other comprehensive loss, net:
Change in unrealized gain (loss) on investments, net of tax	(122)	93	(81)
Comprehensive loss	$ (14,339)	$ (17,174)	$ (17,187)

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	Cash Exercise [Member]	Cash Exercise [Member]Common stock	Cash Exercise [Member]Additional paid-in capital
Balance (shares) at Dec. 31, 2014		25,644,010
Balance at Dec. 31, 2014	$ 109,712	$ 8	$ 202,515	$ (81)	$ (92,730)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (shares)		191,906
Exercise of stock options	1,195		1,195
Vested, Number of Shares							324,178
RSUs released net of shares withheld for tax settlement						$ (1,719)		$ (1,719)
ESPP, Shares Purchased for Award		145,487
Stock Issued During Period, Value, Employee Stock Purchase Plan	1,302		1,302
Vesting of early exercised stock options	12		12
Exercise of common stock warrants										16,741
NoncashCompensationAcquisitionRelatedExpenses	0
Proceeds from Warrant Exercises	111								$ 111		$ 111
Employee stock-based compensation expense	11,005		11,005
Net loss	(17,106)				(17,106)
Other comprehensive income	(81)			(81)
Balance (shares) at Dec. 31, 2015		26,322,322
Balance at Dec. 31, 2015	104,431	$ 8	214,421	(162)	(109,836)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in a public offering		$ 0
Exercise of stock options (shares)		643,005
Exercise of stock options	2,502		2,502
RSUs released net of shares withheld for tax settlement	$ (2,675)							(2,675)
ESPP, Shares Purchased for Award	188,372	188,372
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 1,690		1,690
NoncashCompensationAcquisitionRelatedExpenses	2,632
Proceeds from Warrant Exercises	0
Issuance of restricted stock awards							414,404
Employee stock-based compensation expense	12,035		12,035
Net loss	(17,267)				(17,267)
Other comprehensive income	93			93
Balance (shares) at Dec. 31, 2016		27,568,103
Balance at Dec. 31, 2016	103,441	$ 8	230,605	(69)	(127,103)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (shares)		1,085,041
Exercise of stock options	7,917		7,916
Vested, Number of Shares						944,451
RSUs released net of shares withheld for tax settlement	$ (8,990)							$ (8,990)
ESPP, Shares Purchased for Award	159,532	159,532
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 2,750		2,750
NoncashCompensationAcquisitionRelatedExpenses	0
Proceeds from Warrant Exercises	0
Issuance of restricted stock awards							599,440
Employee stock-based compensation expense	18,196		18,196
Net loss	(14,217)				(14,217)
Other comprehensive income	(122)
Balance (shares) at Dec. 31, 2017		29,412,116
Balance at Dec. 31, 2017	108,975	$ 9	250,854	$ (191)	(141,697)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	(122)
Effect of change in accounting principle related to stock-based compensation	$ 0		$ 377		$ (377)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities
Net loss	$ (14,217)	$ (17,267)	$ (17,106)
Depreciation, Depletion and Amortization	7,643	3,770	3,271
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Inventory provision	380	168	118
Change in lease-related performance liabilities	(864)	(811)	(925)
Share-based Compensation	18,196	12,035	11,005
NoncashCompensationAcquisitionRelatedExpenses	0	2,632	0
Other Operating Activities, Cash Flow Statement	26	42	519
Changes in assets and liabilities
Accounts receivable	(10,963)	(322)	(5,075)
Increase (Decrease) in Other Receivables	41	120	(234)
Inventories	1,361	(1,985)	632
Prepaid expenses and other assets	(866)	(833)	(295)
Accounts payable	(611)	170	1,050
Increase (Decrease) in Other Operating Liabilities	(1,104)	2,355	2,761
Deferred revenue	8,714	11,192	4,144
Net cash provided by (used in) operating activities	7,736	11,266	(135)
Cash flows from investing activities
Payment for purchase of property and equipment	(2,834)	(4,707)	(1,151)
Payments to Acquire Businesses, Net of Cash Acquired	0	(52,500)	0
Purchase of short-term investments	(67,426)	(86,551)	(109,310)
Maturities of short-term investments	53,831	111,809	106,670
Sale of short-term investments	0	32,061	0
Changes in restricted cash	0	0	40
Net cash provided by (used in) investing activities	(16,429)	112	(3,751)
Cash flows from financing activities
Cash from lease-related performance obligations	693	1,596	932
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Excluding Stock Options	2,750	1,690	1,302
Proceeds from exercise of stock options	7,917	2,502	1,195
RSUs released and tax settlement	(8,974)	(2,705)	(1,697)
Proceeds from Warrant Exercises	0	0	111
Net cash provided by financing activities	2,386	3,083	1,843
Net increase (decrease) in cash and cash equivalents	(6,307)	14,461	(2,043)
Cash and cash equivalents at beginning of period	35,033	20,572	22,615
Cash and cash equivalents at end of period	28,726	35,033	20,572
Supplemental cash flow information
Cash paid for income taxes	342	245	159
Supplemental disclosure of non-cash investing and financing activities
Property and equipment in accounts payable and accrued liabilities	$ 102	$ 44	$ 64

The Company and Summary of Sign

The Company and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
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 (the "Company") is a provider of secure, integrated, intelligent communication and clinical workflow solutions, focused on empowering mobile workers in healthcare, hospitality, energy, 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, patient and staff experience and increase operational efficiency. The Vocera Communication and Workflow System is comprised of a unique software platform that connects communication devices, including our hands-free, wearable, voice-controlled communication badges, and third-party mobile devices that use our software applications to our enterprise-class software platform. The system transforms the way mobile workers communicate by enabling them to instantly connect via voice or secure text messaging. With a portfolio of over 120 third-party clinical integrations, our system also enables the intelligent delivery of alerts and alarms to a variety of mobile devices, providing real time situation awareness to care providers. The Company's unique hands-free voice capability allows mobile workers to connect with the right person simply by saying or selecting the name, function or group name of the person they want to reach, often while remaining at the point-of-care. The Company's system responds to over 100 spoken commands. 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, 2017 , had an accumulated deficit of $141.7 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. As of December 31, 2017 , the Company had cash, cash equivalents and short-term investments of $81.2 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, 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, municipal debt 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. The following table presents the changes in the allowance for doubtful accounts: Years ended December 31, (in thousands) 2017 2016 2015 Allowance—beginning of period $ — $ (451 ) $ (53 ) Provisions for bad debts — — (479 ) Recoveries from bad debts — — 60 Write-offs and other — 451 21 Allowance—end of period $ — $ — $ (451 ) 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 component of the Company’s products is currently manufactured by a third-party contractor in Mexico. A significant disruption in the operations of this contractor 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, 2017 and 2016 , no customer accounted for 10% or more of accounts receivable. At December 31, 2017 one reseller represented 26.3% of our accounts receivable. For the years ended December 31, 2017 , 2016 and 2015 , 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 or developed software also generally has a three year useful economic life, except for major ERP implementations, for which the Company assumes a five year useful economic life. 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 discounted 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 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 when development is complete and is amortized on a straight-line basis over the estimated useful life of the related asset, generally three years, except that five years is assumed for major ERP implementations. 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, 2017 , 2016 and 2015 , the Company capitalized costs of $0.3 million , zero and zero , 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, 2017 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 exceeded its carrying value. As of December 31, 2017 , 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, 2017 , 2016 or 2015 . Revenue recognition The Company derives revenue from the sales of badges, smartphones, perpetual software licenses for software that is essential to the functionality of the communication badges, software maintenance, extended product warranty and professional services. The Company also derives revenue from the sale of licenses for software that is not essential to the functionality of the badges, which may include Clinical Integration and Vocera smartphone applications as well as certain subscription-based revenues including Vocera Care Experience. Sales tax is excluded from reported total revenue. Revenue is recognized when all of the below criteria are met: • there is persuasive evidence that an arrangement exists, in the form of a written contract, amendments to that contract, or purchase orders from a third party; • delivery has occurred or services have been rendered; • the price is fixed or determinable after evaluating the risk of concession; and • collectability is reasonably assured based on customer creditworthiness and past history of collection. In arrangements with multiple deliverables, assuming all other revenue criteria are met, the Company recognizes revenue for individual delivered items if they have value to the customer on a standalone basis. The Company allocates arrangement consideration at the inception of the arrangement to all deliverables using the relative selling price method. This method requires the Company to determine the selling price at which each deliverable could be sold if it were sold regularly on a standalone basis. When available, the Company uses vendor-specific objective evidence ("VSOE") of the selling price. VSOE represents the price charged for a deliverable when it is sold separately, or for a deliverable not yet being sold separately, the price established by management with the relevant authority. The Company has established VSOE of the selling price for software maintenance. When VSOE of selling price is not available, third-party evidence ("TPE") of selling price for similar products and services is acceptable; however, the Company's offerings and market strategy differ from those of its competitors, such that the Company cannot obtain sufficient comparable information about third parties' prices. If neither VSOE nor TPE are available, the Company uses its best estimates of selling prices ("BESP"). The Company determines BESP considering factors such as market conditions, sales channels, internal costs and product margin objectives and pricing practices. The Company regularly reviews and update its VSOE and BESP information. The relative selling price method allocates total arrangement consideration proportionally to each deliverable on the basis of its estimated selling price. In addition, the amount recognized for any delivered items cannot exceed that which is contingent upon delivery of any remaining items in the arrangement. A typical sales arrangement involves multiple elements, such as sales of badges, perpetual software licenses, professional services and maintenance services which entitle customers to unspecified upgrades, bug fixes, patch releases and telephone support. Revenue from the sale of badges and perpetual software licenses is recognized upon shipment or delivery at the customers’ premises as the contractual provisions governing sales of these products do not include any provisions regarding acceptance, performance or general right of return or cancellation or termination provisions adversely affecting revenue recognition. Revenue from the sale of maintenance services on software licenses is recognized over the period during which the services are provided, which is generally one year. Revenue from professional services is recognized either on a fixed fee basis based on milestones or on a time and materials basis as the services are provided, both of which generally take place over a period of two to twelve weeks, but may take longer depending on the complexity of the work involved. For non-essential software arrangements with multiple deliverables, including license, professional services and maintenance, the Company recognizes license revenue using the residual method of accounting pursuant to relevant software revenue recognition guidance. Under the residual method, revenue is recognized when VSOE for fair value exists for all of the undelivered elements in the arrangement, but does not exist for one or more of the delivered elements in the arrangement. If evidence of fair value cannot be established for the undelivered elements, all of the revenue is deferred until evidence of fair value can be established, or until the items for which evidence of fair value cannot be established are delivered. The Company has established VSOE for software maintenance. The Company's revenue arrangements do not include a general right of return relative to the delivered products. The Company applies the combined services approach for arrangements in which the Company has VSOE for software maintenance but not for professional services. Under this approach, the Company ratably recognizes revenue over the longer of the period over which professional services is expected to be delivered or the contractual software maintenance period. 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, 2017 , the Company transferred $0.9 million of lease receivables, recording an immaterial net loss and $0.7 million of new financing liabilities for future performance of executory service obligations. For the year ended December 31, 2016 , the Company transferred $3.6 million of lease receivables, recording an immaterial net loss and $1.6 million of new financing liabilities for future performance of executory service obligations. For lease receivables retained as of December 31, 2017 and 2016 , the Company recorded $1.3 million and $1.9 million , respectively, of net investment in sales-type leases, equivalent to the minimum lease payments for the delivered product. Commissions expense Sales commissions are recorded as sales and marketing expense and accrued as a current liability as orders are recorded; thus no contract acquisition costs are capitalized. 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 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 revenues, 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, 2017 , 2016 and 2015 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 For options granted to employees, stock-based compensation is measured at grant date based on the fair value of the award and is expensed on a straight-line basis over the requisite service period. The Company determines the grant date fair value of the options using the Black-Scholes option-pricing model. Restricted stock awards and restricted stock units result in compensation expense, and are recognized on a straight-line basis over the requisite service period, based on the grant date closing stock price. For stock options issued to employees with specific performance criteria, the Company makes a determination at each balance sheet date whether the performance criteria are probable of being achieved. Compensation expense is recognized until such time as the performance criteria are met or when it is probable that the criteria will not be met. 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, 2017 and 2016, respectively. Accordingly, the Company has recorded a full valuation allowance on its deferred tax assets for these years. At December 31, 2017 , the Company had a valuation allowance against net deferred tax assets of $45.3 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 2010 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, 2017 , 2016 and 2015, 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, 2017 , 2016 and 2015 , the Company had revenue transactions with a related party, the University of Chicago Medical Center (UCMC), for $0.4 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 March 2016, the Financial Accounting Standards Board (FASB) issued new guidance related to accounting for stock-based payment award transactions. The guidance is designed to simplify several aspects of accounting for share-based payment award transactions, including the income tax consequences, classification of awards as either equity or liabilities, classification on the statement of cash flows and forfeiture rate calculations. The guidance eliminates the requirement to delay the recognition of excess tax benefits until they reduce current taxes payable. Under this standard, previously unrecognized excess tax benefits shall be recognized on a modified retrospective basis. However, as of January 1, 2017, the previously unrecognized excess tax benefits of $10.4 million had no impact on the Company’s accumulated deficit balance as the related U.S. deferred tax assets were fully offset by a valuation allowance. The guidance also requires excess tax benefits and deficiencies to be recognized prospectively in the provision for income taxes rather than additional paid-in capital. The Company therefore determined that adoption of the new guidance had no material impact on the condensed consolidated statement of operations and the condensed consolidated statement of cash flows. Further, the new guidance eliminates the requirement to estimate forfeitures and reduce stock compensation expense during the vesting period. Instead, companies can elect to account for actual forfeitures as they occur and record any previously unrecognized compensation expense for estimated forfeitures up to the period of adoption as a retrospective adjustment to beginning retained earnings. The Company has made the election to account for actual forfeitures as they occur starting in fiscal year 2017. During the year ended December 31, 2017, the Company recorded a retrospective adjustment to accumulated deficit of $0.4 million . Recent accounting pronouncements In May 2014, the FASB together with the International Accounting Standards Board issued converged guidance for revenue recognition that will replace most existing guidance, eliminate industry-specific guidance and provide a unified model for determining how and when revenue from contracts with customers should be recognized. Under the new guidance, an entity should 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. The new guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (modified retrospective method). The Company adopted the new guidance on January 1, 2018 using the full retrospective method, which requires the Company to present its historical financial information for fiscal years 2016 and 2017 as if the new revenue guidance had been applied to all prior periods. The most significant impact of the standard relates to the timing of revenue recognition for software licenses sold with professional services where the Company did not have vendor specific objective evidence (“VSOE”) for professional services under current guidance. Under the new standard, the requirement to have VSOE for undelivered elements is eliminated and the Company will recognize revenue for software licenses upon transfer of control to its customers. Additionally, the new standard requires the capitalization and amortization of costs related to obtaining a contract, such as sales commissions, which are currently recorded as an expense to sales and marketing at the time they are incurred. The adoption of the standard will result in the recognition of additional revenue of $2.7 million and $4.3 million for the years ended December 31, 2017 and 2016, respectively, an increase in gross profit of $2.7 million and $4.3 million for the years ended December 31, 2017 and 2016, respectively, an increase (decrease) in sales and marketing expense of $0.1 million and $(1.5) million for the years ended December 31, 2017 and 2016, respectively, and a decrease in loss from operations of $2.6 million and $5.8 million for the years ended December 31, 2017 and 2016, respectively. In addition, the adoption of the standard will result in a decrease in total deferred revenue of $7.8 million and $5.2 million as of December 31, 2017 and 2016, respectively, driven primarily by the upfront recognition of software licenses sold with professional services for which the Company does not have VSOE, and an increase in total deferred commissions of $10.3 million and $10.4 million as of December 31, 2017 and 2016, respectively, which wi

Fair value of financial instrum

Fair value of financial instruments	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair value of financial instruments	Fair 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, 2017 , 2016 and 2015 , 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. 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, 2017 and 2016 , respectively. There were no liabilities measured at fair value on a recurring basis for these dates. December 31, 2017 December 31, 2016 (in thousands) Level 1 Level 2 Total Level 1 Level 2 Total Assets Money market funds $ 3,232 $ — $ 3,232 $ 4,996 $ — $ 4,996 Commercial paper — 1,201 1,201 — 1,322 1,322 U.S. government agency securities — 8,648 8,648 — 4,177 4,177 U.S. Treasury securities — 5,561 5,561 — 2,045 2,045 Corporate debt securities — 37,530 37,530 — 33,166 33,166 Total assets measured at fair value $ 3,232 $ 52,940 $ 56,172 $ 4,996 $ 40,710 $ 45,706 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, 2017
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, 2017 (in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair value Cash and cash equivalents: Demand deposits and other cash $ 25,061 $ — $ — $ 25,061 Money market funds 3,232 — — 3,232 Commercial paper — — — — Corporate debt securities 433 — — 433 Total cash and cash equivalents 28,726 — — 28,726 Short-Term Investments: Commercial paper 1,202 — (1 ) 1,201 U.S. government agency securities 8,678 — (30 ) 8,648 U.S. Treasury securities 5,586 — (25 ) 5,561 Corporate debt securities 37,176 1 (80 ) 37,097 Total short-term investments 52,642 1 (136 ) 52,507 Total cash, cash equivalents and short-term investments $ 81,368 $ 1 $ (136 ) $ 81,233 December 31, 2016 (in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair value Cash and cash equivalents: Demand deposits and other cash $ 28,360 $ — $ — $ 28,360 Money market funds 4,996 — — 4,996 Commercial paper 549 — — 549 Corporate debt securities 1,128 — — 1,128 Total cash and cash equivalents 35,033 — — 35,033 Short-Term Investments: Commercial paper 773 — — 773 U.S. government agency securities 4,176 1 — 4,177 U.S. Treasury securities 2,045 — — 2,045 Corporate debt securities 32,052 1 (15 ) 32,038 Total short-term investments 39,046 2 (15 ) 39,033 Total cash, cash equivalents and short-term investments $ 74,079 $ 2 $ (15 ) $ 74,066 The Company has determined that the unrealized losses on its short-term investments as of December 31, 2017 and 2016 do not constitute an "other than temporary impairment". The unrealized losses for the short-term investments as of December 31, 2017 and 2016 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, 2017 Cash and cash equivalents (1) $ 28,726 $ — $ 28,726 Short-term investments 34,750 17,757 52,507 Cash, cash equivalents and short-term investments $ 63,476 $ 17,757 $ 81,233 Balances as of December 31, 2016 Cash and cash equivalents (1) $ 35,033 $ — $ 35,033 Short-term investments 39,033 — 39,033 Cash, cash equivalents and short-term investments $ 74,066 $ — $ 74,066 (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, 2017
Earnings Per Share [Abstract]
Income (loss) per share	oss per share The following table presents the calculation of basic and diluted net income (loss) per share: Years ended December 31, (in thousands, except for share and per share amounts) 2017 2016 2015 Numerator: Net loss $ (14,217 ) $ (17,267 ) $ (17,106 ) Denominator: Weighted-average shares used to compute net loss per common share - basic and diluted 28,655 26,859 25,971 Net loss per share Basic and diluted $(0.50) $(0.64) $(0.66) For the years ended December 31, 2017, 2016 and 2015, 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) 2017 2016 2015 Options to purchase common stock 1,365 2,454 3,355 Warrants to purchase common stock — — 29 Restricted stock units 2,046 2,129 1,322

Goodwill and intangible assets

Goodwill and intangible assets	12 Months Ended
	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and intangible assets	Goodwill and intangible assets Goodwill The Company had $49.2 million and $49.2 million of goodwill as of December 31, 2017 and 2016 , 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, 2017 $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 2017 which determined that no impairment existed. For 2017 and 2016, the Company used the qualitative assessment permitted under authoritative accounting guidance. Among the qualitative factors considered were changes since the prior impairment 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, 2017 , 2016 or 2015 . 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. To date there has been no impairment of the Company's intangible assets. The estimated useful lives and carrying value of acquired intangible assets are as follows: December 31, 2017 December 31, 2016 (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 $ 3,469 $ 7,451 $ 10,920 $ 2,280 $ 8,640 Developed technology 3 to 7 10,050 5,302 4,748 10,050 2,845 7,205 Trademarks 3 to 7 1,110 497 613 1,110 148 962 Backlog 3 1,400 650 750 1,400 78 1,322 Non-compete Agreements 2 to 4 460 455 5 460 389 71 Intangible assets, net book value $ 23,940 $ 10,373 $ 13,567 $ 23,940 $ 5,740 $ 18,200 Amortization of intangible assets was $4.6 million , $1.4 million and $0.8 million for the years ended December 31, 2017 , 2016 and 2015 , 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, 2017 was as follows: (in thousands) Future amortization 2018 $ 4,334 2019 3,880 2020 1,251 2021 1,127 2022 1,050 Thereafter 1,925 Future amortization expense $ 13,567

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2017
Balance Sheet Components [Abstract]
Balance Sheet Components	Consolidated balance sheet components Inventories December 31, (in thousands) 2017 2016 Raw materials $ 4 $ 103 Finished goods 2,811 4,453 Total inventories $ 2,815 $ 4,556 Property and equipment, net December 31, (in thousands) 2017 2016 Computer equipment and software $ 8,832 $ 8,971 Furniture, fixtures and equipment 1,764 1,726 Leasehold improvements 4,794 4,144 Manufacturing tools and equipment 2,624 3,019 Construction in process 157 74 Property and equipment, at cost 18,171 17,934 Less: Accumulated depreciation (12,420 ) (12,040 ) Property and equipment, net $ 5,751 $ 5,894 Depreciation and amortization expense for property and equipment for the years ended December 31, 2017 , 2016 and 2015 was $3.0 million , $2.4 million and $2.5 million , respectively. Net investment in sales-type leases The Company has sales-type leases with terms of 2 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) 2017 2016 Net minimum lease payments to be received $ 2,758 $ 3,566 Less: Unearned interest income and executory revenue portion (1,469 ) (1,704 ) Net investment in sales-type leases 1,289 1,862 Less: Current portion (916 ) (1,066 ) Non-current net investment in sales-type leases $ 373 $ 796 There were no allowances for doubtful accounts on these leases as of December 31, 2017 and 2016 . 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, 2017 were as follows: (in thousands) Future lease payments 2018 $ 1,493 2019 807 2020 418 2021 40 Total $ 2,758 Accrued payroll, restructuring and other current liabilities December 31, (in thousands) 2017 2016 Payroll and related expenses $ 9,569 $ 10,385 Accrued payables 1,801 2,334 Deferred rent, current portion 271 229 Lease financing, current portion 832 801 Product warranty 353 596 Customer prepayments 1,084 769 Sales and use tax payable 505 451 Other 274 331 Total accrued payroll and other current liabilities $ 14,689 $ 15,896 A reconciliation of the changes in the Company’s warranty reserve for the years ended December 31, 2017 , 2016 and 2015 is as follows: Years ended December 31, (in thousands) 2017 2016 2015 Warranty balance at the beginning of the period $ 596 $ 806 $ 497 Warranty expense accrued for shipments during the period 503 757 539 Changes in estimate related to pre-existing warranties (450 ) (537 ) 321 Warranty settlements made (296 ) (430 ) (551 ) Total product warranty $ 353 $ 596 $ 806 Less: Long-term portion $ — $ — $ 105 Current portion of warranty balance at the end of the period $ 353 $ 596 $ 701

Commitments

Commitments	12 Months Ended
	Dec. 31, 2017
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 manufacturer 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, 2017 and 2016 , approximately $4.4 million and $5.4 million , respectively, of raw material inventory was purchased and held by the third-party manufacturer which was subject to such purchase requirements. Leases The Company leases office space for its headquarters and subsidiaries under non-cancelable operating leases, which will expire between January 2018 and March 2022. In April 2015, the Company extended the lease on the San Jose, California headquarters through February 2023. Total rent expense for the years ended December 31, 2017 , 2016 and 2015 was $2.6 million , $2.4 million and $2.3 million , respectively. The Company recognizes rent expense on a straight-line basis over the lease period and has accrued for rent expense incurred but not paid. Future minimum lease payments at December 31, 2017 under non-cancelable operating leases are as follows: (in thousands) Operating leases 2018 $ 2,363 2019 2,190 2020 1,996 2021 1,801 2022 612 2023 35 Total minimum lease payments $ 8,997 Indemnifications The Company undertakes, in the ordinary course of business, to (i) defend customers and other parties from certain third-party claims associated with allegations of trade secret misappropriation, infringement of copyright, patent or other intellectual property right, or tortious damage to persons or property and (ii) indemnify and hold harmless such parties from certain resulting damages, costs and other liabilities. The term of these undertakings may be perpetual and the maximum potential liability of the Company under certain of these undertakings is not determinable. Based on its historical experience, the Company believes the liability associated with these undertakings is minimal. The Company has entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers, other than liabilities arising from willful misconduct of the individual. The Company currently has directors and officers insurance. As there has been no significant history of losses, no expense accrual has been made. 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, 2017
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, 2017 , the Company has 1,297,072 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, 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. Options granted to new hires generally vest over a 4 -year period with 25% vesting at the end of one year and the remaining vest monthly thereafter, options granted as merit awards generally vest monthly over a four-year period. Options granted generally are exercisable up to 10 years . 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, 2016 2,436,845 $ 10.71 5.09 $ 20,643 Options granted — — Options exercised (1,085,041 ) 7.30 Options canceled (19,741 ) 12.11 Outstanding at December 31, 2017 1,332,063 $ 13.48 5.36 $ 22,298 Options vested and expected to vest as of December 31, 2017 1,332,063 $ 13.48 5.36 $ 22,298 Options vested and exercisable as of December 31, 2017 1,203,931 $ 13.78 5.21 $ 19,799 At December 31, 2017 , there was $0.5 million of unrecognized compensation cost related to options which is expected to be recognized over a weighted-average period of 0.73 years. Using the Black-Scholes option-pricing model, the weighted-average grant-date fair value of options granted to employees during the year ended December 31, 2015 was $3.92 per share. No options were granted during the years ended December 31, 2017 and 2016. Further information regarding the value of employee options vested and exercised during the years ended December 31, 2017 , 2016 and 2015 is set forth below. Years ended December 31, (in thousands) 2017 2016 2015 Intrinsic value of options exercised during period $ 18,603 $ 7,816 $ 1,051 The Company uses the Black-Scholes option-pricing model to calculate the fair value of stock options on their grant date. This model requires the following major inputs: the estimated fair value of the underlying common stock, the expected term of the option, the expected volatility of the underlying common stock over the expected life of the option, the risk-free interest rate and expected dividend yield. The following assumptions were used for employee stock-based compensation: Year ended December 31, 2015 Expected term (in years) 5.39 Volatility 41.3% - 41.8% Risk-free interest rate 1.62% - 1.63% Dividend yield 0.0% The computation of expected term is based on the historical exercise and forfeiture behavior of the Company’s employees, giving consideration to the contractual terms of the stock-based awards, vesting schedules and expectations of future employee behavior. For the expected term so determined, the risk-free rate is the U.S. Treasury Rate for that term on the grant date. The Company's expected common stock price volatility is based on the historical volatility of a peer group of publicly-traded companies, using the same expected term. The peer group was selected based on industry and market capitalization data. The Company assumes the dividend yield to be zero , as the Company has never declared or paid dividends and does not expect to do so in the foreseeable future. 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, 2017 and 2016 , employees purchased 159,532 and 188,372 shares, respectively, of common stock at an average purchase price of $17.23 and $8.97 , respectively. As of December 31, 2017 , 584,608 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, 2017 2016 2015 Expected Term (in years) 0.5 0.5 0.5 Volatility 29.0% - 32.0% 32.0% - 41.5% 33.6% - 57.8% Risk-free interest rate 0.61% - 1.39% 0.33% - 0.61% 0.07% - 0.33% Dividend yield 0.0% 0.0% 0.0% Restricted Stock Awards and Restricted Stock Units The Company issues restricted stock awards and RSUs as an element of its compensation plans. A summary of the restricted stock activity for the year ended December 31, 2017 is presented below: Restricted Stock Units Number of shares Weighted Average Grant Date Fair Value per Share Outstanding at December 31, 2016 2,128,735 $ 13.17 Granted 979,387 25.04 Vested (944,451 ) 12.72 Forfeited (118,082 ) 17.02 Outstanding at December 31, 2017 2,045,589 $ 18.84 At December 31, 2017 , there was $28.1 million of unrecognized compensation cost related to RSUs, which is expected to be recognized over a weighted-average period of 1.71 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 year ended December 31, 2017 the straight-line amortization is reduced by actual forfeitures. For the years ended December 31, 2016 and 2015 the straight-line amortization has been reduced for estimated 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) 2017 2016 2015 Cost of revenue $ 2,871 $ 1,388 $ 1,268 Research and development 2,122 1,158 1,072 Sales and marketing 6,563 4,625 4,486 General and administrative 6,640 4,864 4,179 Total stock-based compensation $ 18,196 $ 12,035 $ 11,005

Segments

Segments	12 Months Ended
	Dec. 31, 2017
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) 2017 2016 2015 Revenue Product $ 88,865 $ 70,667 $ 55,716 Service 73,683 57,029 48,370 Total revenue 162,548 127,696 104,086 Cost of revenue Product 27,244 22,788 19,666 Service 37,683 26,287 19,844 Total cost of revenue 64,927 49,075 39,510 Gross profit Product 61,621 47,879 36,050 Service 36,000 30,742 28,526 Total gross profit 97,621 78,621 64,576 Operating expenses 111,641 95,576 81,371 Interest income (expense), net and other 562 217 162 Loss before income taxes $ (13,458 ) $ (16,738 ) $ (16,633 ) 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) 2017 2016 2015 Revenue Product Device $ 60,869 $ 50,061 $ 40,548 Software 27,996 20,606 15,168 Total product 88,865 70,667 55,716 Service Maintenance and support 52,542 43,438 38,443 Professional services and training 21,141 13,591 9,927 Total service 73,683 57,029 48,370 Total revenue $ 162,548 $ 127,696 $ 104,086 The Company’s revenue by geographic region, based on customer location, is summarized as follows: Years ended December 31, (in thousands) 2017 2016 2015 Revenue United States $ 145,548 $ 114,160 $ 94,924 International 17,000 13,536 9,162 Total revenue $ 162,548 $ 127,696 $ 104,086 The Company’s tangible long-lived assets by geographic region, consisting of net property and equipment, are summarized as follows: December 31, (in thousands) 2017 2016 2015 Property and equipment, net United States $ 4,621 $ 5,448 $ 3,335 International 1,130 446 285 Total property and equipment, net $ 5,751 $ 5,894 $ 3,620

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income taxes The components of loss before income taxes are as follows: Years ended December 31, (in thousands) 2017 2016 2015 United States $ (14,250 ) $ (17,365 ) $ (17,041 ) International 792 627 408 Total loss before income taxes $ (13,458 ) $ (16,738 ) $ (16,633 ) The components of the provision for income taxes are as follows: Years ended December 31, (in thousands) 2017 2016 2015 Current Federal $ (10 ) $ — $ — State 54 36 36 Foreign 324 194 275 368 230 311 Deferred Federal 311 334 162 State 119 26 13 Foreign (39 ) (61 ) (13 ) 391 299 162 Total income tax provision $ 759 $ 529 $ 473 The Company had an effective tax rate of (5.6)% , (3.2)% and (2.8)% for the years ended December 31, 2017 , 2016 and 2015 , 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) 2017 2016 2015 U.S. federal (tax benefit) provision at statutory rate $ (4,576 ) $ (5,691 ) $ (5,654 ) State (tax benefit) income taxes, net of federal benefit (437 ) (574 ) (548 ) Foreign income taxes at rates other than the US rate (21 ) (94 ) 119 Stock-based compensation (8,373 ) 581 187 Change in valuation allowance (6,023 ) 6,657 6,764 Non-deductible executive compensation 1,624 — — Rate differential impact on Tax Cuts and Jobs Act 18,975 — — Research and development credits (602 ) (449 ) (537 ) Other 192 99 142 Total $ 759 $ 529 $ 473 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) 2017 2016 Deferred tax assets Net operating loss carryforward $ 27,289 $ 24,239 Research and development credits 5,826 4,705 Depreciation and amortization 2,082 1,845 Reserves and accruals 10,242 11,721 Total deferred tax assets 45,439 42,510 Valuation allowance (45,255 ) (42,339 ) Net deferred tax assets 184 171 Deferred tax liabilities (1,437 ) (1,026 ) Net deferred tax liabilities $ (1,253 ) $ (855 ) 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, 2017 ; accordingly, the Company has recorded a full valuation allowance on its deferred tax assets. On December 22, 2017, the Tax Cuts and Jobs Act (P.L. 115-97) was signed into law. Among other changes is a permanent reduction in the federal corporate income tax rate from 35% to 21% effective January 1, 2018. As a result of the reduction in the corporate income tax rate, the Company has revalued its net deferred tax liability at December 31, 2017. This resulted in a reduction in the value of the Company's net deferred tax asset of approximately $19.0 million , which is offset by the change in valuation allowance of $19.7 million . This resulted in a deferred tax benefit of $0.7 million recorded in the statement of operations in the three months ending December 31, 2017. The Company’s valuation allowance increased by $2.9 million and $6.4 million for the years ended December 31, 2017 and 2016 , respectively. The change in the 2017 valuation allowance was primarily due to the addition of current year loss carryforwards and federal rate reduction. The change in the 2016 valuation allowance was primarily due to the addition of current year loss carryforwards. At December 31, 2017 , the Company had $113.9 million and $56.5 million , respectively, of federal and state net operating loss carryforwards. In addition, the Company has federal research and development tax credits carryforwards of approximately $3.1 million and state research and development tax credit carryforwards of approximately $4.8 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, 2017, $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, 2015: Years Ended December 31, (in thousands) 2017 2016 2015 Balance at the beginning of the period $ 42,339 $ 35,964 $ 30,072 Net operating loss carryforwards generated (utilization) 3,050 2,786 2,263 R&D tax credit increase 1,121 277 1,068 Depreciation and amortization increase 237 938 257 Reserves and accruals increase (decrease) (1,479 ) 2,494 2,327 Deferred tax assets decrease (increase) (13 ) (120 ) (23 ) Balance at the end of the period $ 45,255 $ 42,339 $ 35,964 The following table reflects changes in the unrecognized tax benefits since January 1, 2016: Years ended December 31, (in thousands) 2017 2016 Gross amount of unrecognized tax benefits as of the beginning of the period $ 1,458 $ 1,339 Decreases related to prior year tax provisions — (30 ) Increases related to current year tax provisions 215 149 Gross amount of unrecognized tax benefits as of the end of the period $ 1,673 $ 1,458 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 2017 are subject to tax authority adjustment and all years after 2010 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.

Business Acquisitions (Notes)

Business Acquisitions (Notes)	12 Months Ended
	Dec. 31, 2017
mVisum Net Assets Acquired [Abstract]
Business acquisitions	11. Business acquisitions Acquisition of Extension Healthcare On October 27, 2016 , the Company acquired all of the outstanding equity interest of Extension Healthcare for $52.5 million in cash. The Company incurred $5.8 million in merger and integration costs for the year ended December 31, 2016, which were recorded in cost of revenue and operating expenses in the consolidated statements of operations. Based in Fort Wayne, Ind., Extension Healthcare is a provider of clinical, event-driven communication and workflow collaboration software for the hospital environment. Extension Healthcare is known in the market for its clinical integration software solution Engage, which features an advanced clinical rules engine that unifies data from multiple sources simultaneously, enables prioritization of notifications, adds patient context, and sends messages to the right care team members on their mobile devices. The Engage platform allows clinicians to be away from the bedside while staying informed about their patients. The following table presents the fair value of the identifiable assets acquired and liabilities assumed as of the acquisition date: (in thousands) Fair value of net assets acquired Accounts receivable, net of allowance $ 1,569 Prepaid expenses and other current assets 774 Property and equipment, net 48 Intangibles assets, net 17,200 Goodwill 39,258 Total assets 58,849 Accounts payable (149 ) Accrued payroll and other current liabilities (1,984 ) Deferred revenue, current (2,992 ) Deferred revenue, long-term (1,224 ) Total liabilities assumed (6,349 ) Net assets acquired $ 52,500 The estimated fair values of identifiable intangible assets were primarily determined using discounted cash flow models. The table below shows the valuation of the intangible assets acquired from Extension Healthcare along with their estimated useful lives: (in thousands, except for useful lives) Fair value acquired Useful life (years) Customer relationships $ 8,400 8 Developed technology 6,400 3 Trademarks 1,000 3 Backlog 1,400 3 Total intangible assets $ 17,200 The amortization of developed technology and backlog is recorded in "cost of revenues" for product and the amortization for the remaining intangibles is recorded in "sales and marketing" expenses on the consolidated statement of operations. The excess of the acquisition consideration over the fair values of the underlying net assets acquired was recorded as goodwill. Goodwill is largely attributable to the synergy of Extension Healthcare’s proprietary solutions with the Company’s existing customer base, dedicated sales force and cross selling opportunities with the Company’s other solutions. Goodwill is not amortized but instead is tested for impairment at least annually or more frequently if indicators of impairment are present. For federal income tax purposes, the entire purchase consideration, including goodwill, is capitalizable and deductible over fifteen years. The goodwill recorded from the acquisition of Extension Healthcare was allocated with $31.2 million attributable to the Product reporting unit and $8.0 million attributable to the Service reporting unit. In connection with the acquisition the Company recorded a charge of $2.6 million related to the planned redistribution of proceeds by the selling shareholders to employees of Extension Healthcare who will be retained by the Company post-acquisition. ("Employee Payments"). These payments are not dependent on continued employment with the Company and will be reduced by any escrow claims made by the Company prior to redistribution. Under GAAP, including guidance promulgated by the U.S. Securities and Exchange Commission, actions of economic interest holders in a company may be imputed to the company itself. The selling shareholders of Extension Healthcare meet the criteria of economic interest holders of the Company due to their ability to earn additional consideration in connection with the close of escrow. As such, the redistribution of this portion of the purchase price to the acquired employees who did not have a right to such payments based on their existing interest in Extension Healthcare at the time of acquisition are deemed to represent payments for services that benefit the Company and must therefore be recorded as non-cash compensation expense incurred by the Company and a capital contribution received from the selling shareholders. In substance, the Employee Payments are a second and separate transaction from the acquisition of Extension Healthcare, which is recorded as a separate non-cash accounting entry. Additionally, in connection with the acquisition the Company established a retention bonus plan for Extension Healthcare with potential additional compensation over a two -year period of approximately $2.6 million , based on continued employment. Such amounts are not considered part of the purchase consideration and are being recorded as compensation expense as earned. During the years ended December 31, 2017 and 2016, $1.0 million and $0.5 million , respectively, of this retention bonus was paid and $1.0 million and $0.7 million , respectively, was recorded as compensation expense. Immediately subsequent to the acquisition the Company initiated a restructuring plan which resulted in $0.5 million of severance charges of which $0.1 million was recorded to cost of revenue and $0.4 million was recorded to operating expenses. Substantially all of the amounts have been paid as of December 31, 2016. The results of operations of Extension Healthcare are included in Vocera's consolidated results of operations beginning in the fourth quarter of fiscal 2016. For the fiscal year ended December 31, 2016, immaterial revenue and operating loss of approximately $7.1 million attributable to Extension Healthcare were included in the consolidated results of operations. The unaudited pro forma financial information for the years ended December 31, 2016 and 2015 are presented as if the acquisition had occurred on January 1, 2015. The historical financial information is adjusted in the unaudited pro forma financial information to give effect to pro forma events that are (1) directly attributable to the proposed acquisition, (2) factually supportable, and (3) expected to have a continuing impact on the combined results. The unaudited pro forma financial information are not necessarily indicative of or intended to represent the results that would have been achieved had the transaction been consummated as of the dates indicated or that may be achieved in the future. The actual results reported by the combined company in periods following the acquisition may differ significantly from those reflected in this unaudited pro forma financial information for a number of reasons, including cost saving synergies from operating efficiencies and the effect of the incremental costs incurred to integrate the two companies. Year Ended Year Ended (in thousands) December 31, 2016 December 31, 2015 Revenues $ 134,330 $ 108,793 Net loss $ (31,787 ) $ (40,389 ) Net loss per share attributable to Vocera Basic and diluted $ (1.18 ) $ (1.56 )

Quarterly results of operations

Quarterly results of operations (unaudited) (Notes)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	12. Quarterly results of operations (unaudited) The following tables present certain unaudited consolidated quarterly financial information for each of the eight quarters ended December 31, 2017 . 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) Quarter Ended 2017 March 31, June 30, September 30, December 31, Total revenue $ 36,295 $ 38,450 $ 42,300 $ 45,503 Gross profit $ 20,731 $ 21,681 $ 25,851 $ 29,358 Net loss $ (6,640 ) $ (7,351 ) $ (2,885 ) $ 2,659 Net loss attributable to common stockholders $ (6,640 ) $ (7,351 ) $ (2,885 ) $ 2,659 Net loss per share attributable to common stockholders: Basic $ (0.24 ) $ (0.26 ) $ (0.10 ) $ 0.09 Diluted $ (0.24 ) $ (0.26 ) $ (0.10 ) $ 0.09 Weighted average shares used to compute net income (loss) per share attributable to common stockholders: Basic 27,751 28,422 29,130 29,317 Diluted 27,751 28,422 29,130 30,704 Quarter Ended 2016 March 31, June 30, September 30, December 31, Total revenue $ 26,777 $ 31,152 $ 33,755 $ 36,012 Gross profit $ 16,678 $ 19,074 $ 21,460 $ 21,409 Net loss $ (3,584 ) $ (2,706 ) $ (1,197 ) $ (9,780 ) Net loss attributable to common stockholders $ (3,584 ) $ (2,706 ) $ (1,197 ) $ (9,780 ) Net loss per share attributable to common stockholders: Basic and diluted $ (0.14 ) $ (0.10 ) $ (0.04 ) $ (0.36 ) Weighted average shares used to compute net loss per common share: Basic and diluted 26,379 26,624 27,024 27,409

The Company and Summary of Si20

The Company and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
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, 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, municipal debt 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. The following table presents the changes in the allowance for doubtful accounts: Years ended December 31, (in thousands) 2017 2016 2015 Allowance—beginning of period $ — $ (451 ) $ (53 ) Provisions for bad debts — — (479 ) Recoveries from bad debts — — 60 Write-offs and other — 451 21 Allowance—end of period $ — $ — $ (451 )
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 component of the Company’s products is currently manufactured by a third-party contractor in Mexico. A significant disruption in the operations of this contractor 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, 2017 and 2016 , no customer accounted for 10% or more of accounts receivable. At December 31, 2017 one reseller represented 26.3% of our accounts receivable. For the years ended December 31, 2017 , 2016 and 2015 , 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 or developed software also generally has a three year useful economic life, except for major ERP implementations, for which the Company assumes a five year useful economic life. 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 discounted 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	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 when development is complete and is amortized on a straight-line basis over the estimated useful life of the related asset, generally three years, except that five years is assumed for major ERP implementations. 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, 2017 , 2016 and 2015 , the Company capitalized costs of $0.3 million , zero and zero , 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, 2017 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 exceeded its carrying value. As of December 31, 2017 , 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, 2017 , 2016 or 2015 .
Revenue Recognition, Policy	Revenue recognition The Company derives revenue from the sales of badges, smartphones, perpetual software licenses for software that is essential to the functionality of the communication badges, software maintenance, extended product warranty and professional services. The Company also derives revenue from the sale of licenses for software that is not essential to the functionality of the badges, which may include Clinical Integration and Vocera smartphone applications as well as certain subscription-based revenues including Vocera Care Experience. Sales tax is excluded from reported total revenue. Revenue is recognized when all of the below criteria are met: • there is persuasive evidence that an arrangement exists, in the form of a written contract, amendments to that contract, or purchase orders from a third party; • delivery has occurred or services have been rendered; • the price is fixed or determinable after evaluating the risk of concession; and • collectability is reasonably assured based on customer creditworthiness and past history of collection. In arrangements with multiple deliverables, assuming all other revenue criteria are met, the Company recognizes revenue for individual delivered items if they have value to the customer on a standalone basis. The Company allocates arrangement consideration at the inception of the arrangement to all deliverables using the relative selling price method. This method requires the Company to determine the selling price at which each deliverable could be sold if it were sold regularly on a standalone basis. When available, the Company uses vendor-specific objective evidence ("VSOE") of the selling price. VSOE represents the price charged for a deliverable when it is sold separately, or for a deliverable not yet being sold separately, the price established by management with the relevant authority. The Company has established VSOE of the selling price for software maintenance. When VSOE of selling price is not available, third-party evidence ("TPE") of selling price for similar products and services is acceptable; however, the Company's offerings and market strategy differ from those of its competitors, such that the Company cannot obtain sufficient comparable information about third parties' prices. If neither VSOE nor TPE are available, the Company uses its best estimates of selling prices ("BESP"). The Company determines BESP considering factors such as market conditions, sales channels, internal costs and product margin objectives and pricing practices. The Company regularly reviews and update its VSOE and BESP information. The relative selling price method allocates total arrangement consideration proportionally to each deliverable on the basis of its estimated selling price. In addition, the amount recognized for any delivered items cannot exceed that which is contingent upon delivery of any remaining items in the arrangement. A typical sales arrangement involves multiple elements, such as sales of badges, perpetual software licenses, professional services and maintenance services which entitle customers to unspecified upgrades, bug fixes, patch releases and telephone support. Revenue from the sale of badges and perpetual software licenses is recognized upon shipment or delivery at the customers’ premises as the contractual provisions governing sales of these products do not include any provisions regarding acceptance, performance or general right of return or cancellation or termination provisions adversely affecting revenue recognition. Revenue from the sale of maintenance services on software licenses is recognized over the period during which the services are provided, which is generally one year. Revenue from professional services is recognized either on a fixed fee basis based on milestones or on a time and materials basis as the services are provided, both of which generally take place over a period of two to twelve weeks, but may take longer depending on the complexity of the work involved. For non-essential software arrangements with multiple deliverables, including license, professional services and maintenance, the Company recognizes license revenue using the residual method of accounting pursuant to relevant software revenue recognition guidance. Under the residual method, revenue is recognized when VSOE for fair value exists for all of the undelivered elements in the arrangement, but does not exist for one or more of the delivered elements in the arrangement. If evidence of fair value cannot be established for the undelivered elements, all of the revenue is deferred until evidence of fair value can be established, or until the items for which evidence of fair value cannot be established are delivered. The Company has established VSOE for software maintenance. The Company's revenue arrangements do not include a general right of return relative to the delivered products. The Company applies the combined services approach for arrangements in which the Company has VSOE for software maintenance but not for professional services. Under this approach, the Company ratably recognizes revenue over the longer of the period over which professional services is expected to be delivered or the contractual software maintenance period. 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, 2017 , the Company transferred $0.9 million of lease receivables, recording an immaterial net loss and $0.7 million of new financing liabilities for future performance of executory service obligations. For the year ended December 31, 2016 , the Company transferred $3.6 million of lease receivables, recording an immaterial net loss and $1.6 million of new financing liabilities for future performance of executory service obligations. For lease receivables retained as of December 31, 2017 and 2016 , the Company recorded $1.3 million and $1.9 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, 2017 , the Company transferred $0.9 million of lease receivables, recording an immaterial net loss and $0.7 million of new financing liabilities for future performance of executory service obligations. For the year ended December 31, 2016 , the Company transferred $3.6 million of lease receivables, recording an immaterial net loss and $1.6 million of new financing liabilities for future performance of executory service obligations. For lease receivables retained as of December 31, 2017 and 2016 , the Company recorded $1.3 million and $1.9 million , respectively, of net investment in sales-type leases, equivalent to the minimum lease payments for the delivered product.
Commissions Expense, Policy	Commissions expense Sales commissions are recorded as sales and marketing expense and accrued as a current liability as orders are recorded; thus no contract acquisition costs are capitalized.
Shipping and Handling Costs	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 expenditures Research and development costs are charged to operations as incurred. Software development costs incurred 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 revenues, 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, 2017 , 2016 and 2015 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, 2017 , 2016 and 2015 is as follows: Years ended December 31, (in thousands) 2017 2016 2015 Warranty balance at the beginning of the period $ 596 $ 806 $ 497 Warranty expense accrued for shipments during the period 503 757 539 Changes in estimate related to pre-existing warranties (450 ) (537 ) 321 Warranty settlements made (296 ) (430 ) (551 ) Total product warranty $ 353 $ 596 $ 806 Less: Long-term portion $ — $ — $ 105 Current portion of warranty balance at the end of the period $ 353 $ 596 $ 701
Stock-based Compensation	Stock-based compensation For options granted to employees, stock-based compensation is measured at grant date based on the fair value of the award and is expensed on a straight-line basis over the requisite service period. The Company determines the grant date fair value of the options using the Black-Scholes option-pricing model. Restricted stock awards and restricted stock units result in compensation expense, and are recognized on a straight-line basis over the requisite service period, based on the grant date closing stock price. For stock options issued to employees with specific performance criteria, the Company makes a determination at each balance sheet date whether the performance criteria are probable of being achieved. Compensation expense is recognized until such time as the performance criteria are met or when it is probable that the criteria will not be met.
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, 2017 and 2016, respectively. Accordingly, the Company has recorded a full valuation allowance on its deferred tax assets for these years. At December 31, 2017 , the Company had a valuation allowance against net deferred tax assets of $45.3 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 2010 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 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	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 Income (Loss)	Comprehensive loss For the years ended December 31, 2017 , 2016 and 2015, 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, 2017 , 2016 and 2015 , the Company had revenue transactions with a related party, the University of Chicago Medical Center (UCMC), for $0.4 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 May 2014, the FASB together with the International Accounting Standards Board issued converged guidance for revenue recognition that will replace most existing guidance, eliminate industry-specific guidance and provide a unified model for determining how and when revenue from contracts with customers should be recognized. Under the new guidance, an entity should 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. The new guidance permits two methods of adoption: retrospectively to each prior reporting period presented (full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (modified retrospective method). The Company adopted the new guidance on January 1, 2018 using the full retrospective method, which requires the Company to present its historical financial information for fiscal years 2016 and 2017 as if the new revenue guidance had been applied to all prior periods. The most significant impact of the standard relates to the timing of revenue recognition for software licenses sold with professional services where the Company did not have vendor specific objective evidence (“VSOE”) for professional services under current guidance. Under the new standard, the requirement to have VSOE for undelivered elements is eliminated and the Company will recognize revenue for software licenses upon transfer of control to its customers. Additionally, the new standard requires the capitalization and amortization of costs related to obtaining a contract, such as sales commissions, which are currently recorded as an expense to sales and marketing at the time they are incurred. The adoption of the standard will result in the recognition of additional revenue of $2.7 million and $4.3 million for the years ended December 31, 2017 and 2016, respectively, an increase in gross profit of $2.7 million and $4.3 million for the years ended December 31, 2017 and 2016, respectively, an increase (decrease) in sales and marketing expense of $0.1 million and $(1.5) million for the years ended December 31, 2017 and 2016, respectively, and a decrease in loss from operations of $2.6 million and $5.8 million for the years ended December 31, 2017 and 2016, respectively. In addition, the adoption of the standard will result in a decrease in total deferred revenue of $7.8 million and $5.2 million as of December 31, 2017 and 2016, respectively, driven primarily by the upfront recognition of software licenses sold with professional services for which the Company does not have VSOE, and an increase in total deferred commissions of $10.3 million and $10.4 million as of December 31, 2017 and 2016, respectively, which will be recognized in sales and marketing expense in future periods. The adoption of the standard will not have a significant impact to the provision for income taxes and will not have an impact on net cash provided by or used in operating, investing, or financing activities on the Company's consolidated statements of cash flows. See Expected Impact to Reported Results below for the impact of adoption of the standard on the Company's consolidated balance sheets and consolidated statements of operations. Expected Impact to Reported Results The adoption of the new revenue recognition standard is expected to impact our reported results as follows: Consolidated Statement of Operations Year ended December 31, 2017 (in thousands, except per share data) As Reported Impact of Adoption As Adjusted Revenue Product $ 88,865 $ 2,302 $ 91,167 Service 73,683 410 74,093 Total Revenue $ 162,548 $ 2,712 $ 165,260 Gross Profit $ 97,621 $ 2,712 $ 100,333 Operating Expenses $ 111,641 $ 121 $ 111,762 Loss from Operations $ (14,020 ) $ 2,591 $ (11,429 ) Net Loss $ (14,217 ) $ 2,591 $ (11,626 ) Basic and diluted net loss per share $ (0.50 ) $ 0.09 $ (0.41 ) Consolidated Statement of Operations Year ended December 31, 2016 (in thousands, except per share data) As Reported Impact of Adoption As Adjusted Revenue Product $ 70,667 $ 3,506 $ 74,173 Service 57,029 769 57,798 Total Revenue $ 127,696 $ 4,275 $ 131,971 Gross Profit $ 78,621 $ 4,275 $ 82,896 Operating Expenses $ 95,576 $ (1,537 ) $ 94,039 Loss from Operations $ (16,955 ) $ 5,812 $ (11,143 ) Net Loss $ (17,267 ) $ 5,812 $ (11,455 ) Basic and diluted net loss per share $ (0.64 ) $ 0.22 $ (0.42 ) Consolidated Balance Sheet As of December 31, 2017 (in thousands) As Reported Impact of Adoption As Adjusted Other receivables $ 1,170 $ 161 (2) $ 1,331 Deferred commissions $ — $ 10,301 (1) $ 10,301 Deferred revenue - current $ 47,276 $ (5,760 ) (2) $ 41,516 Deferred revenue - long-term 16,438 (2,021 ) (2) 14,417 Total deferred revenue $ 63,714 $ (7,781 ) $ 55,933 Stockholders' equity $ 108,975 $ 18,243 $ 127,218 Consolidated Balance Sheet As of December 31, 2016 (in thousands) As Reported Impact of Adoption As Adjusted Deferred commissions $ — $ 10,422 (1) $ 10,422 Deferred revenue - current $ 43,845 $ (5,598 ) (2) $ 38,247 Deferred revenue - long-term 11,155 368 (2) 11,523 Total deferred revenue $ 55,000 $ (5,230 ) $ 49,770 Stockholders' equity $ 103,441 $ 15,652 $ 119,093 (1) Impact of cumulative change in commissions expense. (2) Impact of cumulative change in revenue. 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 will also require significant additional disclosures about the amount, timing and uncertainty of cash flows from leases. This new guidance will be effective beginning on 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 has not yet determined the future effect of the standard on its financial position or results of operations. 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 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 October 2016, the FASB issued amended guidance on the accounting for income taxes. The new guidance requires the recognition of the income tax consequences of an intercompany asset transfer, other than transfers of inventory, when the transfer occurs. The guidance will be effective for reporting periods beginning after December 15, 2017, with early adoption permitted. The Company is currently evaluating the impact of this new guidance on its consolidated financial statements, but does not expect that it will have a material impact on its consolidated financial statements. In January 2017, the FASB issued new guidance which clarifies the definition of a business to assist companies with evaluating whether transactions should be accounted for as acquisitions of assets or businesses. The new guidance requires a company to evaluate if substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets; if so, the set of assets and activities is not a business. The guidance also requires a business to include at least one substantive process and narrows the definition of outputs by more closely aligning it with how outputs are described in the guidance for revenue from contracts with customers. The new guidance will be effective for the Company in the first quarter of 2018. Early adoption is permitted. The guidance should be applied prospectively to any transactions occurring within the period of adoption. The adoption of this guidance is not expected to have a material impact on the Company’s 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. In May 2017, the FASB amended the scope of modification accounting for share-based payment arrangements. The guidance clarifies the type of changes to terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting. Specifically, under this guidance, an entity would not apply modification accounting if the fair value, vesting conditions, and classification of the awards are the same immediately before and after the modification. The new standard is effective for the Company in the first quarter of 2018. Early adoption is permitted. The guidance will be applied prospectively to awards modified on or after the adoption date. The Company does not expect the guidance to have a material impact on its consolidated financial statements.

The Company and Summary of Si21

The Company and Summary of Significant Accounting Policies The Company and Summary of Significant Accounting Policies(Tables)	12 Months Ended
	Dec. 31, 2017
Allowance for Doubtful Accounts [Abstract]
New Accounting Pronouncement, Early Adoption [Table Text Block]	The adoption of the new revenue recognition standard is expected to impact our reported results as follows: Consolidated Statement of Operations Year ended December 31, 2017 (in thousands, except per share data) As Reported Impact of Adoption As Adjusted Revenue Product $ 88,865 $ 2,302 $ 91,167 Service 73,683 410 74,093 Total Revenue $ 162,548 $ 2,712 $ 165,260 Gross Profit $ 97,621 $ 2,712 $ 100,333 Operating Expenses $ 111,641 $ 121 $ 111,762 Loss from Operations $ (14,020 ) $ 2,591 $ (11,429 ) Net Loss $ (14,217 ) $ 2,591 $ (11,626 ) Basic and diluted net loss per share $ (0.50 ) $ 0.09 $ (0.41 ) Consolidated Statement of Operations Year ended December 31, 2016 (in thousands, except per share data) As Reported Impact of Adoption As Adjusted Revenue Product $ 70,667 $ 3,506 $ 74,173 Service 57,029 769 57,798 Total Revenue $ 127,696 $ 4,275 $ 131,971 Gross Profit $ 78,621 $ 4,275 $ 82,896 Operating Expenses $ 95,576 $ (1,537 ) $ 94,039 Loss from Operations $ (16,955 ) $ 5,812 $ (11,143 ) Net Loss $ (17,267 ) $ 5,812 $ (11,455 ) Basic and diluted net loss per share $ (0.64 ) $ 0.22 $ (0.42 ) Consolidated Balance Sheet As of December 31, 2017 (in thousands) As Reported Impact of Adoption As Adjusted Other receivables $ 1,170 $ 161 (2) $ 1,331 Deferred commissions $ — $ 10,301 (1) $ 10,301 Deferred revenue - current $ 47,276 $ (5,760 ) (2) $ 41,516 Deferred revenue - long-term 16,438 (2,021 ) (2) 14,417 Total deferred revenue $ 63,714 $ (7,781 ) $ 55,933 Stockholders' equity $ 108,975 $ 18,243 $ 127,218 Consolidated Balance Sheet As of December 31, 2016 (in thousands) As Reported Impact of Adoption As Adjusted Deferred commissions $ — $ 10,422 (1) $ 10,422 Deferred revenue - current $ 43,845 $ (5,598 ) (2) $ 38,247 Deferred revenue - long-term 11,155 368 (2) 11,523 Total deferred revenue $ 55,000 $ (5,230 ) $ 49,770 Stockholders' equity $ 103,441 $ 15,652 $ 119,093 (1) Impact of cumulative change in commissions expense. (2) Impact of cumulative change in revenue.
Allowance for Credit Losses on Financing Receivables [Table Text Block]	The following table presents the changes in the allowance for doubtful accounts: Years ended December 31, (in thousands) 2017 2016 2015 Allowance—beginning of period $ — $ (451 ) $ (53 ) Provisions for bad debts — — (479 ) Recoveries from bad debts — — 60 Write-offs and other — 451 21 Allowance—end of period $ — $ — $ (451 )

Fair value of financial instr22

Fair value of financial instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of assets and liabilities measured at fair value on a recurring basis, by level	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, 2017 and 2016 , respectively. There were no liabilities measured at fair value on a recurring basis for these dates. December 31, 2017 December 31, 2016 (in thousands) Level 1 Level 2 Total Level 1 Level 2 Total Assets Money market funds $ 3,232 $ — $ 3,232 $ 4,996 $ — $ 4,996 Commercial paper — 1,201 1,201 — 1,322 1,322 U.S. government agency securities — 8,648 8,648 — 4,177 4,177 U.S. Treasury securities — 5,561 5,561 — 2,045 2,045 Corporate debt securities — 37,530 37,530 — 33,166 33,166 Total assets measured at fair value $ 3,232 $ 52,940 $ 56,172 $ 4,996 $ 40,710 $ 45,706

Cash, Cash Equivalents and Sh23

Cash, Cash Equivalents and Short-term Investments (Tables)	12 Months Ended
	Dec. 31, 2017
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, 2017 (in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair value Cash and cash equivalents: Demand deposits and other cash $ 25,061 $ — $ — $ 25,061 Money market funds 3,232 — — 3,232 Commercial paper — — — — Corporate debt securities 433 — — 433 Total cash and cash equivalents 28,726 — — 28,726 Short-Term Investments: Commercial paper 1,202 — (1 ) 1,201 U.S. government agency securities 8,678 — (30 ) 8,648 U.S. Treasury securities 5,586 — (25 ) 5,561 Corporate debt securities 37,176 1 (80 ) 37,097 Total short-term investments 52,642 1 (136 ) 52,507 Total cash, cash equivalents and short-term investments $ 81,368 $ 1 $ (136 ) $ 81,233 December 31, 2016 (in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair value Cash and cash equivalents: Demand deposits and other cash $ 28,360 $ — $ — $ 28,360 Money market funds 4,996 — — 4,996 Commercial paper 549 — — 549 Corporate debt securities 1,128 — — 1,128 Total cash and cash equivalents 35,033 — — 35,033 Short-Term Investments: Commercial paper 773 — — 773 U.S. government agency securities 4,176 1 — 4,177 U.S. Treasury securities 2,045 — — 2,045 Corporate debt securities 32,052 1 (15 ) 32,038 Total short-term investments 39,046 2 (15 ) 39,033 Total cash, cash equivalents and short-term investments $ 74,079 $ 2 $ (15 ) $ 74,066
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, 2017 Cash and cash equivalents (1) $ 28,726 $ — $ 28,726 Short-term investments 34,750 17,757 52,507 Cash, cash equivalents and short-term investments $ 63,476 $ 17,757 $ 81,233 Balances as of December 31, 2016 Cash and cash equivalents (1) $ 35,033 $ — $ 35,033 Short-term investments 39,033 — 39,033 Cash, cash equivalents and short-term investments $ 74,066 $ — $ 74,066 (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, 2017
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 income (loss) per share: Years ended December 31, (in thousands, except for share and per share amounts) 2017 2016 2015 Numerator: Net loss $ (14,217 ) $ (17,267 ) $ (17,106 ) Denominator: Weighted-average shares used to compute net loss per common share - basic and diluted 28,655 26,859 25,971 Net loss per share Basic and diluted $(0.50) $(0.64) $(0.66)
Schedule of antidilutive securities excluded from computation of earnings per share	For the years ended December 31, 2017, 2016 and 2015, 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) 2017 2016 2015 Options to purchase common stock 1,365 2,454 3,355 Warrants to purchase common stock — — 29 Restricted stock units 2,046 2,129 1,322

Goodwill and intangible assets

Goodwill and intangible assets (Tables)	12 Months Ended
	Dec. 31, 2017
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. To date there has been no impairment of the Company's intangible assets. The estimated useful lives and carrying value of acquired intangible assets are as follows: December 31, 2017 December 31, 2016 (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 $ 3,469 $ 7,451 $ 10,920 $ 2,280 $ 8,640 Developed technology 3 to 7 10,050 5,302 4,748 10,050 2,845 7,205 Trademarks 3 to 7 1,110 497 613 1,110 148 962 Backlog 3 1,400 650 750 1,400 78 1,322 Non-compete Agreements 2 to 4 460 455 5 460 389 71 Intangible assets, net book value $ 23,940 $ 10,373 $ 13,567 $ 23,940 $ 5,740 $ 18,200 Amortization of intangible assets was $4.6 million , $1.4 million and $0.8 million for the years ended December 31, 2017 , 2016 and 2015 , 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, 2017 was as follows: (in thousands) Future amortization 2018 $ 4,334 2019 3,880 2020 1,251 2021 1,127 2022 1,050 Thereafter 1,925 Future amortization expense $ 13,567

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2017
Balance Sheet Components [Abstract]
Inventories	Inventories December 31, (in thousands) 2017 2016 Raw materials $ 4 $ 103 Finished goods 2,811 4,453 Total inventories $ 2,815 $ 4,556
Property and Equipment	Property and equipment, net December 31, (in thousands) 2017 2016 Computer equipment and software $ 8,832 $ 8,971 Furniture, fixtures and equipment 1,764 1,726 Leasehold improvements 4,794 4,144 Manufacturing tools and equipment 2,624 3,019 Construction in process 157 74 Property and equipment, at cost 18,171 17,934 Less: Accumulated depreciation (12,420 ) (12,040 ) Property and equipment, net $ 5,751 $ 5,894 Depreciation and amortization expense for property and equipment for the years ended December 31, 2017 , 2016 and 2015 was $3.0 million , $2.4 million and $2.5 million , respectively.
Investment in sales-type leases	Net investment in sales-type leases The Company has sales-type leases with terms of 2 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) 2017 2016 Net minimum lease payments to be received $ 2,758 $ 3,566 Less: Unearned interest income and executory revenue portion (1,469 ) (1,704 ) Net investment in sales-type leases 1,289 1,862 Less: Current portion (916 ) (1,066 ) Non-current net investment in sales-type leases $ 373 $ 796 There were no allowances for doubtful accounts on these leases as of December 31, 2017 and 2016 . 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.
Future Minimum Lease Payments for sales-type Leases	The minimum lease payments expected for future years under sales-type leases as of December 31, 2017 were as follows: (in thousands) Future lease payments 2018 $ 1,493 2019 807 2020 418 2021 40 Total $ 2,758
Accrued Liabilities	Accrued payroll, restructuring and other current liabilities December 31, (in thousands) 2017 2016 Payroll and related expenses $ 9,569 $ 10,385 Accrued payables 1,801 2,334 Deferred rent, current portion 271 229 Lease financing, current portion 832 801 Product warranty 353 596 Customer prepayments 1,084 769 Sales and use tax payable 505 451 Other 274 331 Total accrued payroll and other current liabilities $ 14,689 $ 15,896
Product Warranty Disclosure	A reconciliation of the changes in the Company’s warranty reserve for the years ended December 31, 2017 , 2016 and 2015 is as follows: Years ended December 31, (in thousands) 2017 2016 2015 Warranty balance at the beginning of the period $ 596 $ 806 $ 497 Warranty expense accrued for shipments during the period 503 757 539 Changes in estimate related to pre-existing warranties (450 ) (537 ) 321 Warranty settlements made (296 ) (430 ) (551 ) Total product warranty $ 353 $ 596 $ 806 Less: Long-term portion $ — $ — $ 105 Current portion of warranty balance at the end of the period $ 353 $ 596 $ 701
Schedule of Product Warranty Liability	A reconciliation of the changes in the Company’s warranty reserve for the years ended December 31, 2017 , 2016 and 2015 is as follows: Years ended December 31, (in thousands) 2017 2016 2015 Warranty balance at the beginning of the period $ 596 $ 806 $ 497 Warranty expense accrued for shipments during the period 503 757 539 Changes in estimate related to pre-existing warranties (450 ) (537 ) 321 Warranty settlements made (296 ) (430 ) (551 ) Total product warranty $ 353 $ 596 $ 806 Less: Long-term portion $ — $ — $ 105 Current portion of warranty balance at the end of the period $ 353 $ 596 $ 701

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	Future minimum lease payments at December 31, 2017 under non-cancelable operating leases are as follows: (in thousands) Operating leases 2018 $ 2,363 2019 2,190 2020 1,996 2021 1,801 2022 612 2023 35 Total minimum lease payments $ 8,997

Common stock (Tables)

Common stock (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Reserved Shares for Issuance	At December 31, 2017 , the Company has 1,297,072 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, 2016 2,436,845 $ 10.71 5.09 $ 20,643 Options granted — — Options exercised (1,085,041 ) 7.30 Options canceled (19,741 ) 12.11 Outstanding at December 31, 2017 1,332,063 $ 13.48 5.36 $ 22,298 Options vested and expected to vest as of December 31, 2017 1,332,063 $ 13.48 5.36 $ 22,298 Options vested and exercisable as of December 31, 2017 1,203,931 $ 13.78 5.21 $ 19,799
Options, Grants in Period, Wtd Avg Grant Date Fair Value	Using the Black-Scholes option-pricing model, the weighted-average grant-date fair value of options granted to employees during the year ended December 31, 2015 was $3.92 per share. No options were granted during the years ended December 31, 2017 and 2016. Further information regarding the value of employee options vested and exercised during the years ended December 31, 2017 , 2016 and 2015 is set forth below. Years ended December 31, (in thousands) 2017 2016 2015 Intrinsic value of options exercised during period $ 18,603 $ 7,816 $ 1,051
Schedule of Valuation Assumptions for Stock Options	The Company uses the Black-Scholes option-pricing model to calculate the fair value of stock options on their grant date. This model requires the following major inputs: the estimated fair value of the underlying common stock, the expected term of the option, the expected volatility of the underlying common stock over the expected life of the option, the risk-free interest rate and expected dividend yield. The following assumptions were used for employee stock-based compensation: Year ended December 31, 2015 Expected term (in years) 5.39 Volatility 41.3% - 41.8% Risk-free interest rate 1.62% - 1.63% Dividend yield 0.0%
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, 2017 2016 2015 Expected Term (in years) 0.5 0.5 0.5 Volatility 29.0% - 32.0% 32.0% - 41.5% 33.6% - 57.8% Risk-free interest rate 0.61% - 1.39% 0.33% - 0.61% 0.07% - 0.33% 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, 2017 is presented below: Restricted Stock Units Number of shares Weighted Average Grant Date Fair Value per Share Outstanding at December 31, 2016 2,128,735 $ 13.17 Granted 979,387 25.04 Vested (944,451 ) 12.72 Forfeited (118,082 ) 17.02 Outstanding at December 31, 2017 2,045,589 $ 18.84
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) 2017 2016 2015 Cost of revenue $ 2,871 $ 1,388 $ 1,268 Research and development 2,122 1,158 1,072 Sales and marketing 6,563 4,625 4,486 General and administrative 6,640 4,864 4,179 Total stock-based compensation $ 18,196 $ 12,035 $ 11,005

Segments (Tables)

Segments (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Summary of the operating segments	The following table presents a summary of the operating segments: Years ended December 31, (in thousands) 2017 2016 2015 Revenue Product $ 88,865 $ 70,667 $ 55,716 Service 73,683 57,029 48,370 Total revenue 162,548 127,696 104,086 Cost of revenue Product 27,244 22,788 19,666 Service 37,683 26,287 19,844 Total cost of revenue 64,927 49,075 39,510 Gross profit Product 61,621 47,879 36,050 Service 36,000 30,742 28,526 Total gross profit 97,621 78,621 64,576 Operating expenses 111,641 95,576 81,371 Interest income (expense), net and other 562 217 162 Loss before income taxes $ (13,458 ) $ (16,738 ) $ (16,633 )
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) 2017 2016 2015 Revenue Product Device $ 60,869 $ 50,061 $ 40,548 Software 27,996 20,606 15,168 Total product 88,865 70,667 55,716 Service Maintenance and support 52,542 43,438 38,443 Professional services and training 21,141 13,591 9,927 Total service 73,683 57,029 48,370 Total revenue $ 162,548 $ 127,696 $ 104,086
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) 2017 2016 2015 Revenue United States $ 145,548 $ 114,160 $ 94,924 International 17,000 13,536 9,162 Total revenue $ 162,548 $ 127,696 $ 104,086
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) 2017 2016 2015 Property and equipment, net United States $ 4,621 $ 5,448 $ 3,335 International 1,130 446 285 Total property and equipment, net $ 5,751 $ 5,894 $ 3,620

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
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) 2017 2016 2015 United States $ (14,250 ) $ (17,365 ) $ (17,041 ) International 792 627 408 Total loss before income taxes $ (13,458 ) $ (16,738 ) $ (16,633 )
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) 2017 2016 2015 Current Federal $ (10 ) $ — $ — State 54 36 36 Foreign 324 194 275 368 230 311 Deferred Federal 311 334 162 State 119 26 13 Foreign (39 ) (61 ) (13 ) 391 299 162 Total income tax provision $ 759 $ 529 $ 473
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) 2017 2016 2015 U.S. federal (tax benefit) provision at statutory rate $ (4,576 ) $ (5,691 ) $ (5,654 ) State (tax benefit) income taxes, net of federal benefit (437 ) (574 ) (548 ) Foreign income taxes at rates other than the US rate (21 ) (94 ) 119 Stock-based compensation (8,373 ) 581 187 Change in valuation allowance (6,023 ) 6,657 6,764 Non-deductible executive compensation 1,624 — — Rate differential impact on Tax Cuts and Jobs Act 18,975 — — Research and development credits (602 ) (449 ) (537 ) Other 192 99 142 Total $ 759 $ 529 $ 473
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) 2017 2016 Deferred tax assets Net operating loss carryforward $ 27,289 $ 24,239 Research and development credits 5,826 4,705 Depreciation and amortization 2,082 1,845 Reserves and accruals 10,242 11,721 Total deferred tax assets 45,439 42,510 Valuation allowance (45,255 ) (42,339 ) Net deferred tax assets 184 171 Deferred tax liabilities (1,437 ) (1,026 ) Net deferred tax liabilities $ (1,253 ) $ (855 )
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, 2015: Years Ended December 31, (in thousands) 2017 2016 2015 Balance at the beginning of the period $ 42,339 $ 35,964 $ 30,072 Net operating loss carryforwards generated (utilization) 3,050 2,786 2,263 R&D tax credit increase 1,121 277 1,068 Depreciation and amortization increase 237 938 257 Reserves and accruals increase (decrease) (1,479 ) 2,494 2,327 Deferred tax assets decrease (increase) (13 ) (120 ) (23 ) Balance at the end of the period $ 45,255 $ 42,339 $ 35,964
Changes in the unrecognized tax benefits	The following table reflects changes in the unrecognized tax benefits since January 1, 2016: Years ended December 31, (in thousands) 2017 2016 Gross amount of unrecognized tax benefits as of the beginning of the period $ 1,458 $ 1,339 Decreases related to prior year tax provisions — (30 ) Increases related to current year tax provisions 215 149 Gross amount of unrecognized tax benefits as of the end of the period $ 1,673 $ 1,458

Business Acquisitions (Tables)

Business Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2017
Business Acquisition [Line Items]
Schedule of Finite-Lived Intangible Assets Acquired	The table below shows the valuation of the intangible assets acquired from Extension Healthcare along with their estimated useful lives: (in thousands, except for useful lives) Fair value acquired Useful life (years) Customer relationships $ 8,400 8 Developed technology 6,400 3 Trademarks 1,000 3 Backlog 1,400 3 Total intangible assets $ 17,200
Business Acquisition, Pro Forma Information	Year Ended Year Ended (in thousands) December 31, 2016 December 31, 2015 Revenues $ 134,330 $ 108,793 Net loss $ (31,787 ) $ (40,389 ) Net loss per share attributable to Vocera Basic and diluted $ (1.18 ) $ (1.56 )
Extension Healthcare
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	(in thousands) Fair value of net assets acquired Accounts receivable, net of allowance $ 1,569 Prepaid expenses and other current assets 774 Property and equipment, net 48 Intangibles assets, net 17,200 Goodwill 39,258 Total assets 58,849 Accounts payable (149 ) Accrued payroll and other current liabilities (1,984 ) Deferred revenue, current (2,992 ) Deferred revenue, long-term (1,224 ) Total liabilities assumed (6,349 ) Net assets acquired $ 52,500
Net assets of mVisum, Inc. [Member]
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed
Prana Technologies [Member]
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed

Quarterly results of operatio32

Quarterly results of operations (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	12. Quarterly results of operations (unaudited) The following tables present certain unaudited consolidated quarterly financial information for each of the eight quarters ended December 31, 2017 . 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) Quarter Ended 2017 March 31, June 30, September 30, December 31, Total revenue $ 36,295 $ 38,450 $ 42,300 $ 45,503 Gross profit $ 20,731 $ 21,681 $ 25,851 $ 29,358 Net loss $ (6,640 ) $ (7,351 ) $ (2,885 ) $ 2,659 Net loss attributable to common stockholders $ (6,640 ) $ (7,351 ) $ (2,885 ) $ 2,659 Net loss per share attributable to common stockholders: Basic $ (0.24 ) $ (0.26 ) $ (0.10 ) $ 0.09 Diluted $ (0.24 ) $ (0.26 ) $ (0.10 ) $ 0.09 Weighted average shares used to compute net income (loss) per share attributable to common stockholders: Basic 27,751 28,422 29,130 29,317 Diluted 27,751 28,422 29,130 30,704 Quarter Ended 2016 March 31, June 30, September 30, December 31, Total revenue $ 26,777 $ 31,152 $ 33,755 $ 36,012 Gross profit $ 16,678 $ 19,074 $ 21,460 $ 21,409 Net loss $ (3,584 ) $ (2,706 ) $ (1,197 ) $ (9,780 ) Net loss attributable to common stockholders $ (3,584 ) $ (2,706 ) $ (1,197 ) $ (9,780 ) Net loss per share attributable to common stockholders: Basic and diluted $ (0.14 ) $ (0.10 ) $ (0.04 ) $ (0.36 ) Weighted average shares used to compute net loss per common share: Basic and diluted 26,379 26,624 27,024 27,409

The Company and Summary of Si33

The Company and Summary of Significant Accounting Policies Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Sale of Stock [Line Items]
Revenue from Related Parties	$ 400	$ 400	$ 400
Maintenance services revenue recognition period	1 year
Accumulated deficit	$ (141,697)	(127,103)
Cash, Cash Equivalents, and Short-term Investments	81,200
Capitalized Computer Software, Additions	$ 300	$ 0	$ 0
No. of revenue customers with 10% or greater concentration	0	0	0
No of Acct Rec customers with 10% or greater concentration	0	0
Impairment of Intangibles (Excl. Goodwill)	$ 0	$ 0	$ 0
Goodwill, Impairment Loss	$ 0	0	0
No of operating segments	2
Deferred Tax Assets, Valuation Allowance	$ 45,255	42,339	35,964	$ 30,072
Maximum
Sale of Stock [Line Items]
Professional service revenue recognition period	2 months 23 days
Product Liability, Warranty Period	3 years
Minimum
Sale of Stock [Line Items]
Professional service revenue recognition period	14 days
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%
Sharon O'Keefe [Member] | Service | University of Chicago Medical Center [Member]
Sale of Stock [Line Items]
Related Party Transaction, Amounts of Transaction	$ 400	$ 400	$ 300
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

The Company and Summary of Si34

The Company and Summary of Significant Accounting Policies Sales type lease data (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
sales type capital leases transfered to banks	$ 900	$ 3,600
financing liability for future executory services on transfered leases	700	1,600
Capital Leases, Net Investment in Sales Type Leases	$ 1,289	$ 1,862

The Company and Summary of Si35

The Company and Summary of Significant Accounting Policies Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes in Allowance for Doubtful Accounts [Roll Forward]
Allowance—beginning of period	$ 0	$ (451)	$ (53)
Provisions for bad debts	0	0	(479)
Allowance for Loan and Lease Loss, Recovery of Bad Debts	0	0	60
Write-offs and other	0	451	21
Allowance—end of period	$ 0	$ 0	$ (451)

The Company and Summary of Si36

The Company and Summary of Significant Accounting Policies Recently adopted accounting principles (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of change in accounting principle related to stock-based compensation	$ 0
Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred tax assets (increase) decrease	10,400
Effect of change in accounting principle related to stock-based compensation	$ 400

The Company and Summary of Si37

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, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	$ 3,957				$ 3,364				$ 3,957	$ 3,364
Product									88,865	70,667	$ 55,716
Service									73,683	57,029	48,370
Total revenue	45,503	$ 42,300	$ 38,450	$ 36,295	36,012	$ 33,755	$ 31,152	$ 26,777	162,548	127,696	104,086
Gross Profit	29,358	25,851	21,681	20,731	21,409	21,460	19,074	16,678	97,621	78,621	64,576
Operating Expenses									111,641	95,576	81,371
Loss from Operations									(14,020)	(16,955)	(16,795)
Net loss	2,659	$ (2,885)	$ (7,351)	$ (6,640)	$ (9,780)	$ (1,197)	$ (2,706)	$ (3,584)	$ (14,217)	$ (17,267)	$ (17,106)
Basic and diluted					$ (0.36)	$ (0.04)	$ (0.10)	$ (0.14)	$ (0.50)	$ (0.64)	$ (0.66)
Other receivables	1,170				$ 1,211				$ 1,170	$ 1,211
Deferred commissions	0				0				0	0
Deferred revenue, current	47,276				43,845				47,276	43,845
Deferred revenue, long-term	16,438				11,155				16,438	11,155
Deferred Revenue	63,714				55,000				63,714	55,000
Stockholders' equity	108,975				103,441				108,975	103,441
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Product									91,167	74,173
Service									74,093	57,798
Total revenue									165,260	131,971
Gross Profit									100,333	82,896
Operating Expenses									111,762	94,039
Loss from Operations									(11,429)	(11,143)
Net loss									$ (11,626)	$ (11,455)
Basic and diluted									$ (0.41)	$ (0.42)
Other receivables	1,331								$ 1,331
Deferred commissions	10,301				10,422				10,301	$ 10,422
Deferred revenue, current	41,516				38,247				41,516	38,247
Deferred revenue, long-term	14,417				11,523				14,417	11,523
Deferred Revenue	55,933				49,770				55,933	49,770
Stockholders' equity	127,218				119,093				127,218	119,093
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Product									2,302	3,506
Service									410	769
Total revenue									2,712	4,275
Gross Profit									2,712	4,275
Operating Expenses									121	(1,537)
Loss from Operations									2,591	5,812
Net loss									$ 2,591	$ 5,812
Basic and diluted									$ 0.09	$ 0.22
Other receivables	161								$ 161
Deferred commissions	10,301				10,422				10,301	$ 10,422
Deferred revenue, current	(5,760)				(5,598)				(5,760)	(5,598)
Deferred revenue, long-term	(2,021)				368				(2,021)	368
Deferred Revenue	(7,781)				(5,230)				(7,781)	(5,230)
Stockholders' equity	$ 18,243				$ 15,652				$ 18,243	$ 15,652

Fair value of financial instr38

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, 2017	Dec. 31, 2016
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	$ 28,726	$ 35,033
Available-for-sale Securities	52,507	39,033
Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Total assets measured at fair value	56,172	45,706
Fair Value, Measurements, Recurring | Level 1
Assets, Fair Value Disclosure [Abstract]
Total assets measured at fair value	3,232	4,996
Fair Value, Measurements, Recurring | Level 2
Assets, Fair Value Disclosure [Abstract]
Total assets measured at fair value	52,940	40,710
Fair Value, Measurements, Recurring | Money Market Funds [Member]
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	3,232	4,996
Fair Value, Measurements, Recurring | Money Market Funds [Member] | Level 1
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	3,232	4,996
Fair Value, Measurements, Recurring | Money Market Funds [Member] | Level 2
Assets, Fair Value Disclosure [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring | Commercial paper
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	1,201	1,322
Fair Value, Measurements, Recurring | Commercial paper | Level 1
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring | Commercial paper | Level 2
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	1,201	1,322
Fair Value, Measurements, Recurring | U.S. government agency securities
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	8,648	4,177
Fair Value, Measurements, Recurring | U.S. government agency securities | Level 1
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring | U.S. government agency securities | Level 2
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	8,648	4,177
Fair Value, Measurements, Recurring | US Treasury Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	5,561	2,045
Fair Value, Measurements, Recurring | US Treasury Securities [Member] | Level 1
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring | US Treasury Securities [Member] | Level 2
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	5,561	2,045
Fair Value, Measurements, Recurring | Corporate Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	37,530	33,166
Fair Value, Measurements, Recurring | Corporate Debt Securities [Member] | Level 1
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring | Corporate Debt Securities [Member] | Level 2
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities	$ 37,530	$ 33,166

Cash, Cash Equivalents and Sh39

Cash, Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Cash and cash equivalents:
Amortized Cost	$ 28,726	$ 35,033
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair value	28,726	35,033
Short-Term Investments:
Amortized Cost	52,642	39,046
Unrealized Gains	1	2
Unrealized Losses	(136)	(15)
Fair value	52,507	39,033
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Amortized Cost	81,368	74,079
Unrealized Gains	1	2
Unrealized Losses	(136)	(15)
Fair value	81,233	74,066
Commercial paper
Short-Term Investments:
Amortized Cost	1,202	773
Unrealized Gains	0	0
Unrealized Losses	(1)	0
Fair value	1,201	773
U.S. government agency securities
Short-Term Investments:
Amortized Cost	8,678	4,176
Unrealized Gains	0	1
Unrealized Losses	(30)	0
Fair value	8,648	4,177
US Treasury Securities [Member]
Short-Term Investments:
Amortized Cost	5,586	2,045
Unrealized Gains	0	0
Unrealized Losses	(25)	0
Fair value	5,561	2,045
Corporate Debt Securities [Member]
Short-Term Investments:
Amortized Cost	37,176	32,052
Unrealized Gains	1	1
Unrealized Losses	(80)	(15)
Fair value	37,097	32,038
Demand deposis and other cash
Cash and cash equivalents:
Amortized Cost	25,061	28,360
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair value	25,061	28,360
Money Market Funds [Member]
Cash and cash equivalents:
Amortized Cost	3,232	4,996
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair value	3,232	4,996
Commercial paper
Cash and cash equivalents:
Amortized Cost	0	549
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair value	0	549
Corporate Debt Securities [Member]
Cash and cash equivalents:
Amortized Cost	433	1,128
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair value	$ 433	$ 1,128

Cash, Cash Equivalents and Sh40

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, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	$ 28,726	$ 35,033
Available-for-sale Securities	52,507	39,033
Cash, Cash Equivalents And Short Term Investments, Fair Value Disclosure	81,233	74,066
Maturity up to one year [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	28,726	35,033
Available-for-sale Securities	34,750	39,033
Cash, Cash Equivalents And Short Term Investments, Fair Value Disclosure	63,476	74,066
maturity between 1 and 2 years [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Available-for-sale Securities	17,757	0
Cash, Cash Equivalents And Short Term Investments, Fair Value Disclosure	$ 17,757	$ 0

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, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Numerator:
Net loss	$ 2,659	$ (2,885)	$ (7,351)	$ (6,640)	$ (9,780)	$ (1,197)	$ (2,706)	$ (3,584)	$ (14,217)	$ (17,267)	$ (17,106)
Net (loss) income attributable to common stockholders	$ 2,659	$ (2,885)	$ (7,351)	$ (6,640)	$ (9,780)	$ (1,197)	$ (2,706)	$ (3,584)
Net Income (Loss) Available to Common Stockholders, Diluted									$ (14,217)	$ (17,267)	$ (17,106)
Denominator:
Weighted-average shares used to compute net loss per common share - basic and diluted									28,655	26,859	25,971
Weighted average shares used to compute diluted income (loss) per common share									28,655	26,859	25,971
Net loss per share
Basic and diluted					$ (0.36)	$ (0.04)	$ (0.10)	$ (0.14)	$ (0.50)	$ (0.64)	$ (0.66)

Income (loss) per share Sched42

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, 2017	Dec. 31, 2016	Dec. 31, 2015
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	1,365	2,454
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			3,355
Warrants 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	0	0	29
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,046	2,129	1,322

Goodwill and intangible asset43

Goodwill and intangible assets Schedule of Finite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ 10,373	$ 5,740
Finite-Lived Intangible Assets, Net	13,567
Intangible Assets, Gross (Excluding Goodwill)	23,940	23,940
Intangible assets, net	13,567	18,200
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	4,600	1,400	$ 800
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	10,920	10,920
Accumulated amortization	3,469	2,280
Finite-Lived Intangible Assets, Net	7,451	8,640
Technology-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	10,050	10,050
Accumulated amortization	5,302	2,845
Finite-Lived Intangible Assets, Net	4,748	7,205
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,110	1,110
Accumulated amortization	497	148
Finite-Lived Intangible Assets, Net	613	962
Backlog
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,400	1,400
Accumulated amortization	650	78
Finite-Lived Intangible Assets, Net	750	1,322
Non-compete Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	460	460
Accumulated amortization	455	389
Finite-Lived Intangible Assets, Net	$ 5	$ 71
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 asset44

Goodwill and intangible assets Future amortization schedule (Details) $ in Thousands	Dec. 31, 2017USD ($)
Goodwill and intangible assets [Abstract]
2,017	$ 4,334
2,018	3,880
2,019	1,251
2,020	1,127
2,021	1,050
Thereafter	1,925
Finite-Lived Intangible Assets, Net	$ 13,567

Balance Sheet Components Invent

Balance Sheet Components Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory, Net [Abstract]
Raw materials	$ 4	$ 103
Finished goods	2,811	4,453
Total inventories	$ 2,815	$ 4,556

Balance Sheet Components Proper

Balance Sheet Components Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	$ 18,171	$ 17,934
Less: Accumulated depreciation	(12,420)	(12,040)
Property and equipment, net	5,751	5,894	$ 3,620
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	8,832	8,971
Furniture, fixtures and equipment
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	1,764	1,726
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	4,794	4,144
Manufacturing tools and equipment
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	2,624	3,019
Construction in process
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, gross	$ 157	$ 74

Balance Sheet Components Deprec

Balance Sheet Components Depreciation, depletion, amortization (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property-Equipment Deepreciation and amortization [Abstract]
Depreciation and amortization	$ 3	$ 2.4	$ 2.5

Balance Sheet Components Balanc

Balance Sheet Components Balance sheet components - investment in sales type leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Investment in Sales Type Leases
Capital Leases, Net Investment in Sales Type Leases, Minimum Payments to be Received	$ 2,758	$ 3,566
Capital Leases, Net Investment in Sales Type Leases, Deferred Income	(1,469)	(1,704)
Capital Leases, Net Investment in Sales Type Leases	1,289	1,862
Capital Leases, Lessor Balance Sheet, Net Investment in Sales Type Leases, Current	(916)	(1,066)
Capital Leases, Lessor Balance Sheet, Net Investment in Sales Type Leases, Noncurrent	$ 373	$ 796
Minimum
Lease Term [Abstract]
Lessor Leasing Arrangements, Operating Leases, Term of Contract	2 years
Maximum
Lease Term [Abstract]
Lessor Leasing Arrangements, Operating Leases, Term of Contract	4 years

Balance Sheet Components Bala49

Balance Sheet Components Balance sheet components - sales type lease Future Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Lessors schedule of future minimum lease payments [Line Items]
Capital Leases, Future Minimum Payments Due, Next Twelve Months	$ 1,493
Capital Leases, Future Minimum Payments Due in Two Years	807
Capital Leases, Future Minimum Payments Due in Three Years	418
Capital Leases, Future Minimum Payments Due in Four Years	40
Capital Leases, Net Investment in Sales Type Leases, Minimum Payments to be Received	$ 2,758	$ 3,566

Balance Sheet Components Accrue

Balance Sheet Components Accrued Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Balance Sheet Components [Abstract]
Product Warranty Accrual, Payments	$ 296	$ 430	$ 551
Accrued Liabilities, Current [Abstract]
Payroll and related expenses	9,569	10,385
Accrued payables	1,801	2,334
Deferred rent, current portion	271	229
Lease financing, current portion	832	801
Product warranty	353	596
Customer Refund Liability, Current	1,084	769
Sales and use tax payable	505	451
Other	274	331
Total accrued payroll and other current liabilities	$ 14,689	$ 15,896

Balance Sheet Components Bala51

Balance Sheet Components Balance sheet components Product Warranties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
movement in std product warranty liability [Roll Forward]
Warranty balance at the beginning of the period	$ 596	$ 701	$ 497
Warranty expense accrued for shipments during the period	503	757	539
Changes in estimate related to pre-existing warranties	(450)	(537)	321
Warranty settlements made	(296)	(430)	(551)
Current portion of warranty balance at the end of the period	353	596	701
Product Warranty Accrual	353	596	806
Product Warranty Accrual, Noncurrent	$ 0	$ 0	$ 105

Commitments Schedule of Future

Commitments Schedule of Future Minimum Rental Payments for Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leases, Rent Expense, Net [Abstract]
Rent expense	$ 2,600	$ 2,400	$ 2,300
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,017	2,363
2,018	2,190
2,019	1,996
2,020	1,801
2,021	612
Thereafter	35
Total minimum lease payments	8,997
Inventories
Unrecorded Unconditional Purchase Obligation [Line Items]
Non-cancelable purchase commitment with a third party manufacturer to purchase inventory	$ 4,400	$ 5,400

Common stock (Details)

Common stock (Details) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
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, 2017shares
Options to purchase common stock
Class of Stock [Line Items]
Common stock (in shares)	1,297,072

Common stock (Incentive stock o

Common stock (Incentive stock option plans) (Details)	12 Months Ended
	Dec. 31, 2017
Class of Stock [Line Items]
Number of equity incentive plans	4
Stock options | 2012 Plan
Class of Stock [Line Items]
Vesting period (in years)	4 years
Award vesting percentage at end of one year (percent)	25.00%
Expiration period of granted options (in years)	10 years

Common stock (Options outstandi

Common stock (Options outstanding) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair value (in dollars per share)			$ 3.92
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)	1,332,063
Options vested and expected to vest (Wtd avg exercise price)	$ 13.48
Options vested and expected to vest (Wtd avg remaining contractual term)	5 years 4 months 10 days
Options vested and expected to vest (Aggregate intrinsic value)	$ 22,298
Options vested and exercisable (Number of options)	1,203,931
Options vested and exercisable (Wtd avg exercise price)	$ 13.78
Options vested and exercisable (Wtd avg remaining contractual term)	5 years 2 months 16 days
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized net compensation cost related to options	$ 500
Weighted average period (in years)	8 months 23 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Options, Outstanding, Beginning balance	2,436,845
Options granted	0
Options exercised	(1,085,041)
Number of Options, Outstanding, Ending balance	1,332,063	2,436,845
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price, Outstanding, Beginning balance	$ 10.71
Wtd Avg Remaining Contractual Term, Options Outstanding	5 years 4 months 10 days	5 years 1 month 2 days
Options granted	$ 0
Options exercised	7.30
Weighted Average Exercise Price, Outstanding, Ending balance	$ 13.48	$ 10.71
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period	19,741
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 12.11
Share-based Compensation Arrangement by Share-based Payment Award, Options, Aggregate Intrinsic Value [Abstract]
Aggregate Intrinsic Value, Options Outstanding	$ 22,298	$ 20,643

Common stock (Fair value option

Common stock (Fair value option pricing model) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2017
Options - intrinsic value and grant date fair value [Abstract]
Options vested and exercisable (Aggregate intrinsic value)				$ 19,799
Weighted-average grant-date fair value (in dollars per share)			$ 3.92
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%
Stock options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (years)			5 years 4 months 20 days
Expected Volatility Rate			41.30%
Risk-free interest rate			1.62%
Stock options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (years)			5 years 4 months 20 days
Expected Volatility Rate			41.80%
Risk-free interest rate			1.63%

Common stock (Employee options

Common stock (Employee options vested and exercised) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Exercises in Period, Total Intrinsic Value	$ 18,603	$ 7,816	$ 1,051

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, 2017	Dec. 31, 2016
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	$ 0
Outstanding, Number of Shares	2,045,589	2,128,735
Outstanding, Wtd Ag Grant Date Fair Value	$ 18.84	$ 13.17
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, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average period (in years)	1 year 8 months 16 days
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, Number of Shares	2,128,735
Granted, Number of Shares	979,387
Vested, Number of Shares	944,451
Forfeited, Number of Shares	118,082
Outstanding, Number of Shares	2,045,589
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Granted, Wtd Avg Grant Date Fair Value	$ 25.04
Vested, Wtd Avg Grant Date Fair Value	12.72
Forfeitured, Wtd Avg Grant Date Fair Value	17.02
Outstanding, Wtd Ag Grant Date Fair Value	$ 18.84	$ 13.17

Common stock (Unrecognized net

Common stock (Unrecognized net compensation) (Details)	12 Months Ended
	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%

Common stock (Granted employee

Common stock (Granted employee and nonemployee options) (Details)	12 Months Ended
	Dec. 31, 2015$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair Value of Common Stock per Share	$ 3.92

Common stock (Nonemployee stock

Common stock (Nonemployee stock-based compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 18,196	$ 12,035	$ 11,005

Common stock (Recognized expens

Common stock (Recognized expenses nonemployee stock-based compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Goods and Nonemployee Services Transaction [Line Items]
Stock-based compensation expense	$ 18,196	$ 12,035	$ 11,005

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, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 18,196	$ 12,035	$ 11,005
Cost of Sales [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	2,871	1,388	1,268
Research and Development Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	2,122	1,158	1,072
Selling and Marketing Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	6,563	4,625	4,486
General and Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 6,640	$ 4,864	$ 4,179

Common stock Common Stock (ESPP

Common stock Common Stock (ESPP B-S-M option pricing model assumptions) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ESPP plan details [Abstract]
Stock Shares Issued During Period, ESPP	159,532	188,372
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%	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	$ 17.23	$ 8.97
Common stock (in shares) reserved for ESPP	584,608
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	29.00%	32.00%	33.60%
Risk-free interest rate	0.61%	0.33%	0.07%
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	32.00%	41.50%	57.80%
Risk-free interest rate	1.39%	0.61%	0.33%

Common stock Common stock and p

Common stock Common stock and preferred stock warrants (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Proceeds from Warrant Exercises	$ 0	$ 0	$ 111
Cash Exercise [Member]
Proceeds from Warrant Exercises			$ 111

Segments Summary of the operati

Segments Summary of the operating segments (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments									2
Revenue
Product									$ 88,865	$ 70,667	$ 55,716
Service									73,683	57,029	48,370
Total revenue	$ 45,503	$ 42,300	$ 38,450	$ 36,295	$ 36,012	$ 33,755	$ 31,152	$ 26,777	162,548	127,696	104,086
Cost of revenue
Product									27,244	22,788	19,666
Service									37,683	26,287	19,844
Cost of Goods and Services Sold									64,927	49,075	39,510
Gross Profit [Abstract]
Gross Profit, Goods									61,621	47,879	36,050
Gross Profit, Services									36,000	30,742	28,526
Gross profit	$ 29,358	$ 25,851	$ 21,681	$ 20,731	$ 21,409	$ 21,460	$ 19,074	$ 16,678	97,621	78,621	64,576
Operating Expenses									111,641	95,576	81,371
Interest income (expense) and other									562	217	162
Loss before income taxes									$ (13,458)	$ (16,738)	$ (16,633)

Segments Summary of revenue by

Segments Summary of revenue by product line (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue from External Customer [Line Items]
Product									$ 88,865	$ 70,667	$ 55,716
Service									73,683	57,029	48,370
Total revenue	$ 45,503	$ 42,300	$ 38,450	$ 36,295	$ 36,012	$ 33,755	$ 31,152	$ 26,777	162,548	127,696	104,086
Devices
Revenue from External Customer [Line Items]
Product									60,869	50,061	40,548
Software
Revenue from External Customer [Line Items]
Product									27,996	20,606	15,168
Maintenance and support
Revenue from External Customer [Line Items]
Service									52,542	43,438	38,443
Professional services and training
Revenue from External Customer [Line Items]
Service									$ 21,141	$ 13,591	$ 9,927

Segments Schedule of revenue by

Segments Schedule of revenue by geographic region (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Geographic Areas, Revenues from External Customers [Abstract]
Total revenue	$ 45,503	$ 42,300	$ 38,450	$ 36,295	$ 36,012	$ 33,755	$ 31,152	$ 26,777	$ 162,548	$ 127,696	$ 104,086
Geographic Areas, Long-Lived Assets [Abstract]
Property and equipment, net	$ 5,751				$ 5,894				$ 5,751	$ 5,894	$ 3,620
Concentration Risks, Types, No Concentration Percentage [Abstract]
No. of revenue customers with 10% or greater concentration									0	0	0
No of Acct Rec customers with 10% or greater concentration	0				0				0	0
United States
Geographic Areas, Revenues from External Customers [Abstract]
Total revenue									$ 145,548	$ 114,160	$ 94,924
Geographic Areas, Long-Lived Assets [Abstract]
Property and equipment, net	$ 4,621				$ 5,448				4,621	5,448	3,335
International
Geographic Areas, Revenues from External Customers [Abstract]
Total revenue									17,000	13,536	9,162
Geographic Areas, Long-Lived Assets [Abstract]
Property and equipment, net	$ 1,130				$ 446				$ 1,130	$ 446	$ 285

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
United States	$ (14,250)	$ (17,365)	$ (17,041)
International	792	627	408
Total loss before income taxes	$ (13,458)	$ (16,738)	$ (16,633)

Income Taxes (Components of the

Income Taxes (Components of the provision (benefit) for income taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current
Federal	$ (10)	$ 0	$ 0
State	54	36	36
Foreign	324	194	275
Current Income Tax Expense (Benefit)	368	230	311
Deferred
Federal	311	334	162
State	119	26	13
Foreign	(39)	(61)	(13)
Deferred Income Tax Expense (Benefit)	391	299	162
Total income tax provision	$ 759	$ 529	$ 473

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, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
U.S. federal (tax benefit) provision at statutory rate	$ (4,576)	$ (5,691)	$ (5,654)
State (tax benefit) income taxes, net of federal benefit	(437)	(574)	(548)
Foreign income taxes at rates other than the US rate	(21)	(94)	119
Nondeductible Share-based Compensation Cost	(8,373)	581	187
Change in valuation allowance	(6,023)	6,657	6,764
Research and development credits	(602)	(449)	(537)
Other	192	99	142
Total income tax provision	$ 759	$ 529	$ 473
Effective Income Tax Rate, Percent [Abstract]
Effective tax rate	(5.60%)	(3.20%)	(2.80%)
Income Tax Rate Reconciliation Nondeductible Expense, Warrants	$ 1,624	$ 0	$ 0
Income Tax Rate Reconciliation Nondeductible Expense, Acquisition Costs	$ 18,975	$ 0	$ 0

Income Taxes (Deferred tax asse

Income Taxes (Deferred tax assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Net operating loss carryforward	$ 27,289	$ 24,239
Research and development credits	5,826	4,705
Deferred Tax Assets, Property, Plant and Equipment	2,082	1,845
Reserves and accruals	10,242	11,721
Total deferred tax assets	45,439	42,510
Valuation allowance	(45,255)	(42,339)	$ (35,964)	$ (30,072)
Net deferred tax assets	184	171
Deferred tax liabilities	(1,437)	(1,026)
Net deferred tax liabilities	(1,253)	(855)
Decrease in deferred tax asset due to change in tax rate	19,000
Change in valuation allowance, due to tax change	19,700
Deferred tax benefit, due to change in tax rate	(700)
Deferred tax assets (increase) decrease	$ (2,900)	$ (6,400)

Income Taxes (Tax carry forward

Income Taxes (Tax carry forwards) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	$ 500
Research and development credits	5,826	$ 4,705
Deferred tax assets decrease	$ (2,900)	$ (6,400)
Tax Credit Carryforward, Limitations on Use	600,000
Federal | Federal R&D tax credits carryforwards [Member]
Tax Credit Carryforward [Line Items]
Research and development credits	$ 3,100
State | State R&D tax credits carryforwards [Member]
Tax Credit Carryforward [Line Items]
Research and development credits	$ 4,800

Income Taxes Income Taxes (Oper

Income Taxes Income Taxes (Operating Loss Carryovers) (Details)	12 Months Ended
	Dec. 31, 2017USD ($)
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Limitations on Use	$ 11,500,000
Document Period End Date	Dec. 31, 2017
Operating Loss Carryforwards	$ 5,300,000
Federal
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	113,900,000
State
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	$ 56,500,000

Income Taxes (income Taxes) DTA

Income Taxes (income Taxes) DTA Valuation Allowance Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes (DTA Valuation Allowance Rollforward) [Abstract]
Balance at the beginning of the period	$ 42,339	$ 35,964	$ 30,072
Net operating loss carryforwards generated (utilization)	3,050	2,786	2,263
R&D tax credit increase	1,121	277	1,068
Depreciation and amortization increase	237	938	257
Reserves and accruals increase (decrease)	(1,479)	2,494	2,327
Deferred tax assets decrease (increase)	(13)	(120)	(23)
Balance at the end of the period	$ 45,255	$ 42,339	$ 35,964

Income Taxes (Changes in unreco

Income Taxes (Changes in unrecognized tax benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
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	$ 1,458	$ 1,339
Decreases related to prior year tax provisions	0	(30)
Increases related to current year tax provisions	215	149
Gross amount of unrecognized tax benefits as of the end of the period	$ 1,673	$ 1,458

Business Acquisitions Acquisiti

Business Acquisitions Acquisition of mVisium Net Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 49,246	$ 49,246
Minimum [Member] | Technology-Based Intangible Assets [Member]
Business Acquisition [Line Items]
Weighted average useful life (years)	3 years
Minimum [Member] | Non-compete Agreements
Business Acquisition [Line Items]
Weighted average useful life (years)	2 years
Minimum [Member] | Customer relationships
Business Acquisition [Line Items]
Weighted average useful life (years)	7 years
Minimum [Member] | Trademarks and Trade Names [Member]
Business Acquisition [Line Items]
Weighted average useful life (years)	3 years
Maximum [Member] | Technology-Based Intangible Assets [Member]
Business Acquisition [Line Items]
Weighted average useful life (years)	7 years
Maximum [Member] | Non-compete Agreements
Business Acquisition [Line Items]
Weighted average useful life (years)	4 years
Maximum [Member] | Customer relationships
Business Acquisition [Line Items]
Weighted average useful life (years)	9 years
Maximum [Member] | Trademarks and Trade Names [Member]
Business Acquisition [Line Items]
Weighted average useful life (years)	7 years

Business Acquisitions Acquisi80

Business Acquisitions Acquisition of Prana Technologies assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 49,246	$ 49,246

Business Acquisitions Acquisi81

Business Acquisitions Acquisition of Extension Healthcare (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 27, 2016	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 49,246	$ 49,246	$ 49,246
Pro Forma Revenue				134,330	$ 108,793
Pro Forma Net Loss		7,100		$ (31,787)	$ (40,389)
Pro Forma, Earnings Per Share, Basic And Diluted (in dollars per share)				$ (1,180)	$ (1,560)
Extension Healthcare
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 52,500
Business Acquisition, Transaction Costs		$ 5,800		$ 5,800
Accounts receivable, net of allowance	1,569
Prepaid expenses and other current assets	774
Property and equipment, net	48
Intangibles assets, net	17,200
Goodwill	39,258
Total assets	58,849
Accounts payable	(149)
Accrued payroll and other current liabilities	(1,984)
Deferred revenue, current	(2,992)
Deferred revenue, long-term	(1,224)
Total liabilities assumed	6,349
Net assets acquired	52,500
Recorded charge for planned redistribution of proceeds	2,600
Customer relationships | Extension Healthcare
Business Acquisition [Line Items]
Intangibles assets, net	$ 8,400
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	8 years
Developed technology | Extension Healthcare
Business Acquisition [Line Items]
Intangibles assets, net	$ 6,400
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	3 years
Trademarks | Extension Healthcare
Business Acquisition [Line Items]
Intangibles assets, net	$ 1,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	3 years
Backlog | Extension Healthcare
Business Acquisition [Line Items]
Intangibles assets, net	$ 1,400
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	3 years
Product Segment
Business Acquisition [Line Items]
Goodwill			41,200
Product Segment | Extension Healthcare
Business Acquisition [Line Items]
Goodwill	$ 31,200
Service Segment
Business Acquisition [Line Items]
Goodwill			8,000
Service Segment | Extension Healthcare
Business Acquisition [Line Items]
Goodwill	$ 8,000
Retention Bonus Plan | Extension Healthcare
Business Acquisition [Line Items]
Retention Bonus Plan, additional compensation period	2 years
Retention Bonus Plan, additional compensation	$ 2,600
Retention Bonus Plan, amounts paid			1,000	500
Retention Bonus Plan, amounts recorded as expense			$ 1,000	700
Employee Severance | Extension Healthcare
Business Acquisition [Line Items]
Severance costs				500
Cost of revenue | Employee Severance | Extension Healthcare
Business Acquisition [Line Items]
Severance costs				100
Operating expense | Employee Severance | Extension Healthcare
Business Acquisition [Line Items]
Severance costs				$ 400

Quarterly results of operatio82

Quarterly results of operations (unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Total Revenue	$ 45,503	$ 42,300	$ 38,450	$ 36,295	$ 36,012	$ 33,755	$ 31,152	$ 26,777	$ 162,548	$ 127,696	$ 104,086
Gross Profit	29,358	25,851	21,681	20,731	21,409	21,460	19,074	16,678	97,621	78,621	64,576
Net loss	2,659	(2,885)	(7,351)	(6,640)	(9,780)	(1,197)	(2,706)	(3,584)	$ (14,217)	$ (17,267)	$ (17,106)
Net Income (Loss) Available to Common Stockholders, Basic	$ 2,659	$ (2,885)	$ (7,351)	$ (6,640)	$ (9,780)	$ (1,197)	$ (2,706)	$ (3,584)
Basic and diluted					$ (0.36)	$ (0.04)	$ (0.10)	$ (0.14)	$ (0.50)	$ (0.64)	$ (0.66)
Weighted Average Number of Shares Outstanding, Basic					27,409	27,024	26,624	26,379