PROS (PRO) 10-Q 26 Oct 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 23, 2017
Entity Information [Line Items]
Entity Registrant Name	PROS HOLDINGS, INC.
Entity Central Index Key	1,392,972
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		31,906,987
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 157,359	$ 118,039
Short-term Investments	0	15,996
Accounts and unbilled receivables, net	34,641	33,285
Prepaid and other current assets	12,123	6,337
Total current assets	204,123	173,657
Property and equipment, net	14,471	15,238
Intangible Assets, Net (Excluding Goodwill)	28,972	12,650
Goodwill	38,309	20,096
Other long term assets, net	6,754	6,013
Total assets	292,629	227,654
Current liabilities:
Accounts payable	4,203	2,744
Accrued liabilities	7,693	7,279
Accrued payroll and other employee benefits	13,312	18,349
Deferred revenue	73,092	68,349
Total current liabilities	98,300	96,721
Long-term deferred revenue	18,672	11,389
Convertible Debt, Noncurrent	210,312	122,299
Other Liabilities, Noncurrent	756	639
Total liabilities	328,040	231,048
Commitments and contingencies (Note 6)
Stockholders' equity:
Preferred stock, $0.001 par value, 5,000,000 shares authorized; none issued	0	0
Common stock, $0.001 par value, 75,000,000 shares authorized; 36,319,135 and 35,001,236 shares issued, respectively; 31,901,550 and 30,583,651 shares outstanding, respectively	36	35
Additional paid-in capital	202,905	175,678
Treasury stock, 4,417,585 common shares, at cost	(13,938)	(13,938)
Retained earnings (Accumulated deficit)	(221,205)	(160,259)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(3,209)	(4,910)
Total stockholders' equity	(35,411)	(3,394)
Total liabilities and stockholders' equity	$ 292,629	$ 227,654

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Allowance for bad debts	$ 760,000	$ 760,000
Preferred stock - par value	$ 0.001	$ 0.001
Preferred stock - shares authorized	5,000,000	5,000,000
Preferred stock - shares issued	0	0
Common stock - par value	$ 0.001	$ 0.001
Common stock - shares authorized	75,000,000	75,000,000
Common stock - shares issued	36,319,135	35,001,236
Common stock - shares outstanding	31,901,550	30,583,651
Treasury stock - shares	4,417,585	4,417,585

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue:
Subscription	$ 15,809	$ 9,852	$ 41,457	$ 27,196
Maintenance and support	17,124	17,666	52,332	51,103
Total subscription, maintenance and support revenue	32,933	27,518	93,789	78,299
License	603	2,419	3,883	8,178
Services	8,401	8,447	24,800	26,873
Total revenue	41,937	38,384	122,472	113,350
Cost of revenue:
Cost of subscription	7,868	4,808	19,605	12,342
Cost of maintenance and support	2,859	3,416	8,886	10,266
Cost of subscription, maintenance and support	10,727	8,224	28,491	22,608
Cost of license	73	38	210	199
Cost of services	6,924	7,380	21,718	24,594
Cost of Revenue	17,724	15,642	50,419	47,401
Gross profit	24,213	22,742	72,053	65,949
Operating Expenses
Selling and Marketing Expense	16,980	13,641	50,625	47,725
General and Administrative Expense	10,324	9,253	30,514	27,910
Research and development	14,046	12,964	42,429	39,454
Business Combination, Acquisition Related Costs	613	0	613	0
Income from operations	(17,750)	(13,116)	(52,128)	(49,140)
Other income (expense):
Convertible debt interest and amortization	(4,094)	(2,339)	(9,078)	(6,943)
Other Nonoperating Income (Expense)	347	(26)	315	(139)
Loss before income tax provision	(21,497)	(15,481)	(60,891)	(56,222)
Income tax provision (benefit)	(271)	227	55	490
Net income (loss)	$ (21,226)	$ (15,708)	$ (60,946)	$ (56,712)
Earnings Per Share, Basic	$ (0.67)	$ (0.52)	$ (1.93)	$ (1.87)
Net earnings (loss) per share:
Earnings Per Share, Basic and Diluted	$ (0.67)	$ (0.52)	$ (1.93)	$ (1.87)
Weighted average number of shares:
Weighted Average Number of Shares Outstanding, Basic and Diluted	31,867	30,469	31,527	30,341
Other comprehensive income, net of tax:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	$ 329	$ 176	$ 1,705	$ 538
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	6	(8)	(4)	18
Other comprehensive income	335	168	1,701	556
Comprehensive income (loss)	$ (20,891)	$ (15,540)	$ (59,245)	$ (56,156)

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities:
Net income (loss)	$ (60,946)	$ (56,712)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, Depletion and Amortization	7,047	7,396
Amortization of Financing Costs and Discounts	6,363	4,786
Share-based compensation	17,665	14,445
Deferred Income Tax Expense (Benefit)	(453)	64
Provision for doubtful accounts	0	(226)
Changes in operating assets and liabilities:
Accounts and unbilled receivables	(141)	12,899
Prepaid expenses and other assets	(6,301)	(746)
Accounts payable	1,734	(2,546)
Accrued liabilities	(473)	887
Accrued payroll and other employee benefits	(5,722)	709
Deferred revenue	11,379	11,885
Net cash provided by (used in) operating activities	(29,848)	(7,159)
Investing activities:
Purchases of property and equipment	(1,235)	(6,524)
Payments to Acquire Businesses, Net of Cash Acquired	(34,130)	0
Internal-use software development costs capitalized	(1,996)	(569)
Payments to Acquire Intangible Assets	(75)	0
Payments to Acquire Short-term Investments	0	(144,934)
Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities	15,992	96,500
Net cash provided by (used in) investing activities	(21,444)	(55,527)
Financing activities:
Exercise of stock options	6,347	420
Proceeds from Stock Plans	1,535	1,090
Tax withholding related to net share settlement of restricted stock units	(7,243)	(5,244)
Repayments of Notes Payable	(155)	(196)
Proceeds from Convertible Debt	93,500	0
Net cash provided by (used in) financing activities	91,161	(3,930)
Effect of Exchange Rate on Cash and Cash Equivalents	(549)	54
Net change in cash and cash equivalents	39,320	(66,562)
Cash and cash equivalents:
Beginning of period	118,039	161,770
End of period	157,359	95,208
Revolving Credit Facility [Member]
Financing activities:
Payments of Debt Issuance Costs	(150)	0
Convertible Debt [Member]
Financing activities:
Payments of Debt Issuance Costs	$ (2,673)	$ 0

Organization and Nature of Oper

Organization and Nature of Operations	9 Months Ended
	Sep. 30, 2017
Organization and Nature of Operations [Abstract]
Organization and nature of operations	Organization and Nature of Operations PROS Holdings, Inc., a Delaware corporation, through its operating subsidiaries (collectively, the "Company"), is a cloud software company powering the shift to modern commerce by helping companies create personalized and frictionless buying experiences for their customers. Fueled by dynamic pricing science and machine learning, PROS solutions make it possible for companies to price, configure and sell their products and services in an omnichannel environment with speed, precision and consistency. PROS customers, who are leaders in their markets, benefit from decades of data science expertise infused into its industry solutions. The Company provides its solutions to enterprises across the manufacturing, distribution, and services industries, including automotive and industrial, business-to-business ("B2B") services, cargo, chemicals and energy, consumer goods, insurance, food and beverage, healthcare, high tech, and travel. The Company offers its solutions via a SaaS delivery model as well as on a more limited basis, via perpetual licenses. The Company also provides professional services to implement its software applications as well as business consulting. In addition, the Company provides product maintenance and support to its customers through which they receive unspecified upgrades, maintenance releases and bug fixes during the term of the support period on a when-and-if-available basis.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Notes)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	2. Summary of Significant Accounting Policies The accompanying unaudited condensed consolidated financial statements reflect the application of significant accounting policies as described below and elsewhere in these notes to the condensed consolidated financial statements. Basis of presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with generally accepted accounting principles in the United States ("GAAP") for interim financial reporting and applicable quarterly reporting regulations of the Securities and Exchange Commission ("SEC"). In management's opinion, the accompanying interim unaudited condensed consolidated financial statements include all adjustments necessary for a fair statement of the financial position of the Company as of September 30, 2017 , the results of operations for the three and nine months ended September 30, 2017 and 2016 , and cash flows for the nine months ended September 30, 2017 and 2016 . Certain information and disclosures normally included in the notes to the annual financial statements prepared in accordance with GAAP have been omitted from these interim unaudited condensed consolidated financial statements pursuant to the rules and regulations of the SEC. Accordingly, these unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2016 ("Annual Report") filed with the SEC. The condensed consolidated balance sheet as of December 31, 2016 was derived from the Company's audited consolidated financial statements but does not include all disclosures required under GAAP. Basis of consolidation The unaudited condensed consolidated financial statements include the accounts of the Company, its wholly owned subsidiaries and a subsidiary where the Company exercises control. All intercompany transactions and balances have been eliminated in consolidation. The functional currency of PROS France SAS, formerly known as Cameleon Software SA ("PROS France") is the Euro. The financial statements of this subsidiary are translated into U.S. dollars using period-end rates of exchange for assets and liabilities, historical rates of exchange for equity, and average rates of exchange for the period for revenue and expenses. Translation gains (losses) are recorded in accumulated other comprehensive loss as a component of stockholders' equity. Dollar amounts The dollar amounts presented in the tabular data within these footnote disclosures are stated in thousands of dollars, except per share amounts, or as noted within the context of each footnote disclosure. Use of estimates The Company makes estimates and assumptions in the preparation of its unaudited condensed consolidated financial statements, and its estimates and assumptions may affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated financial statements, and the reported amounts of revenue and expenses during the reporting periods. Actual results could differ from those estimates. The complexity and judgment required in the Company's estimation process, as well as issues related to the assumptions, risks and uncertainties inherent in the application of the percentage-of-completion method of accounting, affect the amounts of revenue, expenses, unbilled receivables and deferred revenue. Estimates are also used for, but not limited to, receivables, allowance for doubtful accounts, useful lives of assets, depreciation and amortization, income taxes and deferred tax asset valuation, valuation of stock options, other current liabilities and accrued liabilities. Numerous internal and external factors can affect estimates. The critical accounting policies related to the estimates and judgments are discussed in the Company's Annual Report under management's discussion and analysis of financial condition and results of operations. There have been no significant changes to the Company's critical accounting policies as described in the Company's Annual Report. Revenue recognition The Company derives its revenues primarily from subscription services fees, professional services, the perpetual licensing of its software products and the associated software maintenance and support services. The Company commences revenue recognition when all of the following criteria are met: • there is persuasive evidence of an arrangement; • the service has been or is being provided to the customer; • collection of the fee is reasonably assured; and • the amount of fees to be paid by the customer is fixed and determinable. Subscription services revenue Subscription services revenue is generally recognized ratably over the contractual term of the arrangement beginning on the date that the Company's service is made available to the customer, assuming all other revenue recognition criteria have been met. The Company's subscription contracts do not provide customers with the right to take possession of the software supporting the applications and, as a result, are accounted for as service contracts. Any revenue related to up-front activation or set-up fees are deferred and recognized ratably over the estimated period that the customer benefits from the related services. Direct and incremental costs related to up-front activation or set-up activities are capitalized until the date the Company's service is made available and then expensed ratably over the estimated period that the customer benefits from the related services. For the Company's subscription services that include professional services, the Company determines whether the professional services have standalone value. Professional services deemed to have standalone value are accounted for separately from subscription services and the subscription services revenue recognition commences on the date that the Company's service is made available to the customer. If determined that the professional services do not have standalone value, the transaction is treated as a single element and the subscription services and professional services revenue is deferred until the customer commences use of the subscription services, and the subscription services revenue is recognized over the remaining term of the arrangement. Maintenance and support revenue Maintenance and support revenue includes post-implementation customer support and the right to unspecified software updates and enhancements on a when-and-if-available basis. The Company recognizes revenue from maintenance arrangements ratably over the period in which the services are provided. License revenue The Company derives the majority of its license revenue from the sale of perpetual licenses. For software license arrangements that do not require significant modification or customization of the underlying software, the Company recognizes software licenses revenues upon software delivery, assuming all other revenue recognition criteria have been met. The Company evaluates the nature and scope of professional services for each arrangement, and if it determines that the professional services revenue should not be accounted for separately from license revenue, the license revenue is recognized together with the professional services revenue using the percentage-of-completion method or completed contract method. The completed contract method is also used for contracts where there is a risk over final acceptance by the customer or for contracts that are short-term in nature. The percentage-of-completion method is measured by the percentage of man-days incurred during the reporting period as compared to the estimated total man-days necessary for each contract for implementation of the software solutions. The Company believes that for each such project, man-days expended in proportion to total estimated man-days at completion represents the most reliable and meaningful measure for determining a project's progress toward completion. Under the Company's fixed-fee arrangements, should a loss be anticipated on a contract, the full amount of the loss is recorded when the loss is determinable. The Company also licenses software solutions under term license agreements that typically include maintenance during the license term. When maintenance is included for the entire term of the term license, there is no renewal rate and the Company has not established vendor specific objective evidence ("VSOE") of fair value for the maintenance on term licenses. For term license agreements, revenue and the associated costs are deferred until the delivery of the solution and recognized ratably over the remaining license term. Professional services revenue Professional services revenues are generally recognized as the services are rendered for time and material contracts, or on a proportional performance basis for fixed price contracts. The majority of the Company's professional services contracts are on a time and materials basis. Training revenues are recognized as the services are rendered. For the Company's subscription services that include professional services, the Company determines whether the professional services have standalone value. Professional services deemed to have standalone value are accounted for separately from subscription services and typically recognized as the services are performed. If determined that the professional services do not have standalone value, the transaction is treated as a single element, the professional services revenue is deferred until the customer commences use of the subscription services, and the professional services revenue is recognized over the remaining term of the arrangement. For software license arrangements that include professional services, the Company determines whether the professional services are considered essential to the functionality of the software using factors such as: the nature of its software products; whether they are ready for use by the customer upon receipt; the nature of professional services; the availability of services from other vendors; whether the timing of payments for license revenue coincides with performance of services; and whether milestones or acceptance criteria exist that affect the realizability of the software license fee. For professional services considered essential to the functionality of the software, the license revenue is recognized together with the professional services revenue using the percentage-of-completion method or completed contract method. The completed contract method is also used for contracts where there is a risk over final acceptance by the customer or for contracts that are short-term in nature. Multiple element arrangements For arrangements with multiple deliverables, the Company evaluates whether the individual deliverables qualify as separate units of accounting. In order to treat deliverables in a multiple deliverable arrangement as separate units of accounting, the deliverables must have standalone value upon delivery. If the deliverables have standalone value upon delivery, the Company accounts for each deliverable separately and revenue is recognized for the respective deliverables as they are delivered. When multiple deliverables included in an arrangement are separable into different units of accounting, the arrangement consideration is allocated to the identified separate units of accounting based on their relative selling price. Multiple deliverable arrangement accounting guidance provides a hierarchy when determining the relative selling price for each unit of accounting. VSOE of selling price, based on the price at which the item is regularly sold by the vendor on a standalone basis, should be used if it exists. If VSOE of selling price is not available, third-party evidence ("TPE") of selling price is used to establish the selling price if it exists. If neither VSOE nor TPE exist for a deliverable, arrangements with multiple deliverables can be separated into discrete units of accounting based on the Company's best estimate of selling price ("BESP"). The objective of BESP is to determine the price at which the Company would transact a sale if the product or service were sold on a standalone basis. The amount of arrangement fee allocated is limited by contingent revenues, if any. For transactions that only include software and software-related elements, the Company continues to account for such arrangements under the software revenue recognition standards which require it to establish VSOE of fair value to allocate arrangement consideration to multiple deliverables. For multiple-element arrangements that contain software and nonsoftware elements such as its subscription services, the Company allocates revenue between the software and software related elements as a group and any nonsoftware elements based on a relative fair value allocation. The Company determines fair value for each deliverable using the selling price hierarchy described above and utilizing VSOE of fair value if it exists. The Company applies the residual method to recognize revenue for the delivered elements in standalone software transactions. Under the residual method, the amount of revenue allocated to delivered elements equals the total arrangement consideration, less the aggregate fair value of any undelivered elements, typically maintenance, provided that VSOE of fair value exists for all undelivered elements. VSOE of fair value is based on the price charged when the element is sold separately or, in the case of maintenance, substantive renewal rates for maintenance. Revenue that has been recognized, but for which the Company has not invoiced the customer, is recorded as unbilled receivables. Invoices that have been issued before revenue has been recognized are recorded as deferred revenue in the accompanying consolidated balance sheets. Business Combinations The Company records tangible and intangible assets acquired and liabilities assumed in business combinations under the acquisition method of accounting. Amounts paid for each acquisition are allocated to the assets acquired and liabilities assumed based on their fair values at the date of acquisition. Significant management judgments and assumptions are required in determining the fair value of acquired assets and liabilities, particularly acquired intangible assets. The valuation of purchased intangible assets is based upon estimates of the future performance and cash flows from the acquired business. Each asset is measured at fair value from the perspective of a market participant. The Company uses its best estimates and assumptions to accurately assign fair value to the tangible and intangible assets acquired and liabilities assumed at the acquisition date. The Company’s estimates are inherently uncertain and subject to refinement. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the fair value of these tangible and intangible assets acquired and liabilities assumed, with the corresponding offset to goodwill. In addition, uncertain tax positions and tax-related valuation allowances are initially established in connection with a business combination as of the acquisition date. The Company continues to collect information and reevaluates these estimates and assumptions quarterly and records any adjustments to the Company’s preliminary estimates to goodwill, provided that the Company is within the measurement period. Upon the conclusion of the measurement period or final determination of the fair value of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the Company’s condensed consolidated statements of operations. Internal-use software Costs incurred to develop internal-use software during the development stage are capitalized, stated at cost, and depreciated using the straight-line method over the estimated useful lives of the assets. Development stage costs generally include salaries and personnel costs and third-party contractor expenses associated with internal-use software configuration, coding, installation and testing. For the three months ended September 30, 2017 and 2016 , the Company capitalized $0.7 million and $0.5 million , respectively, and for the nine months ended September 30, 2017 and 2016 , the Company capitalized $2.2 million and $0.6 million , respectively, of internal-use software development costs related to cloud-based offerings. Capitalized internal-use software development costs related to cloud-based offerings are amortized using the straight-line method over the useful life of the asset. For the three and nine months ended September 30, 2017 , the Company amortized an immaterial amount of capitalized internal-use software development costs. For the three and nine months ended September 30, 2016 , the Company amortized no capitalized internal-use software development costs. Capitalized software for internal use is included in property and equipment, net in the unaudited condensed consolidated balance sheets. Amortization of capitalized internal-use software development costs, once it commences, is included in cost of subscription revenues in the accompanying unaudited condensed consolidated statements of comprehensive income (loss). Impairment of long-lived assets Long-lived assets are reviewed for impairment whenever an event or change in circumstances indicates that the carrying amount of an asset or group of assets may not be recoverable. The impairment review includes comparison of future cash flows expected to be generated by the asset or group of assets with the associated assets' carrying value. If the carrying value of the asset or group of assets exceeds its expected future cash flows (undiscounted and without interest charges), an impairment loss is recognized to the extent that the carrying amount of the asset exceeds its fair value. The Company recorded no impairment charges during the three and nine months ended September 30, 2017 and 2016 . Noncash share-based compensation The Company measures all share-based payments to its employees based on the grant date fair value of the awards and recognizes expenses in the Company's unaudited consolidated statement of comprehensive income (loss) on a straight-line basis over the periods during which the recipient is required to perform services (generally over the vesting period of the awards). To date, the Company has granted stock options, Restricted Stock Units ("RSUs"), stock settled Stock Appreciation Rights ("SARs"), and Market Stock Units ("MSUs"). RSUs include (i) time-based awards, and (ii) market-based awards in which the number of shares that vest are based upon attainment of target average per share closing price over a requisite trading period. MSUs are performance-based awards in which the number of shares that vest are based upon the Company's relative stockholder return. The following table presents the number of shares or units outstanding for each award type as of September 30, 2017 and December 31, 2016 , respectively, (in thousands): Award type September 30, 2017 December 31, 2016 Stock options 148 734 Restricted stock units (time-based) 2,180 2,237 Restricted stock units (market-based) 345 460 Stock appreciation rights 391 515 Market stock units 347 342 Stock options, time-based RSUs and SARs vest ratably between one and four years. Market-based RSUs vest if the average trailing closing price of the Company's Common Stock meets certain minimum performance hurdles for at least 105 calendar days prior to September 9, 2020, with 25% vesting at $27 , an additional 25% vesting at $33 , and the remaining 50% vesting at $41 . The actual number of MSUs that will be eligible to vest is based on the total stockholder return of the Company relative to the total stockholder return of the Russell 2000 Index ("Index") over their respective performance periods, as defined by each award's plan documents. The Company did not grant any stock options or SARs during the three and nine months ended September 30, 2017 or 2016 . The fair value of the time-based RSUs is based on the closing price of the Company's stock on the date of grant. The Company estimates the fair value and the derived service period of the market-based RSUs on the date of grant using a Monte Carlo simulation model. The model requires the use of a number of assumptions including the expected volatility of the Company's stock, its risk-free interest rate and expected dividends. The Company's expected volatility at the date of grant was based on the historical volatility of the Company over the performance period. The fair value of the market-based RSUs is expensed over the derived service period for each separate vesting tranche. The derived service period for the vesting tranches of the market-based RSUs ranges between 1.01 and 1.98 years. The Company estimates the fair value of MSUs on the date of grant using a Monte Carlo simulation model. The determination of fair value of the MSUs is affected by the Company's stock price and a number of assumptions including the expected volatilities of the Company's stock and the Index, its risk-free interest rate and expected dividends. The Company's expected volatility at the date of grant was based on the historical volatilities of the Company and the Index over the performance period. The weighted average assumptions used to value the MSUs granted during the three and nine months ended September 30, 2017 were as follows: September 30, 2017 Volatility 45.88% Risk-free interest rate 1.52% Expected option life in years 3.10 Dividend yield — Earnings per share The Company computes basic earnings (loss) per share by dividing net income (loss) attributable to common stockholders by the weighted average number of common shares outstanding. Diluted earnings (loss) per share is computed by dividing net income (loss) attributable to common stockholders by the weighted average number of common shares and dilutive potential common shares then outstanding. Diluted earnings per share reflect the assumed conversion of all dilutive securities, using the treasury stock method. Dilutive potential common shares consist of shares issuable upon the exercise of stock options, shares of unvested restricted stock units, and settlement of stock appreciation rights. When the Company incurs a net loss, the effect of the Company's outstanding stock options, stock appreciation rights and restricted stock units are not included in the calculation of diluted earnings (loss) per share as the effect would be anti-dilutive. Accordingly, basic and diluted net loss per share are identical. Short-term investments The Company's investments are available-for-sale commercial paper and certificate of deposit that are recorded at fair value in the consolidated balance sheets. The Company classifies all commercial paper regardless of original maturity at purchase date as investments. Unrealized gains and losses on available-for-sale securities are recorded, net of tax, as a component of accumulated other comprehensive income (loss), unless impairment is considered to be other-than-temporary. Other-than-temporary unrealized losses on available-for-sale securities are generally recorded in gain (loss) on investments, net, in the consolidated statements of comprehensive income (loss) unless certain criteria are met. The primary factors considered when determining if a charge must be recorded because a decline in the fair value of an investment is other-than-temporary include whether: (i) the fair value of the investment is significantly below the Company's cost basis; (ii) the financial condition of the issuer of the security has deteriorated; (iii) if a debt security, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the security; (iv) the decline in fair value has existed for an extended period of time; (v) if a debt security, such security has been downgraded by a rating agency; and (vi) the Company has the intent and ability to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value. Investments with remaining maturities of twelve months or less are classified as short-term investments since they are readily convertible to cash to fund short-term operations. Investments with remaining maturities of more than twelve months are classified as long-term investments. All of the Company's investments had contractual maturities of less than twelve months as of September 30, 2017 . Cost method investment Investments in equity securities of privately held companies without readily determinable fair value, where the Company does not exercise significant influence over the investee, are recorded using the cost method of accounting, carrying the investment at historical cost. If there are no identified events or changes in circumstances that might have an adverse effect on the cost method investments, the Company does not estimate the investments' fair value. For all investments, if a decline in the fair value of an investment below the carrying value is determined to be other-than-temporary, such investment is written down to its estimated fair value with a charge to current earnings. At September 30, 2017 and December 31, 2016 , the Company held $2.0 million of equity securities in a privately held company. This investment is accounted for under the cost method and the Company measures it at fair value on a nonrecurring basis when it is deemed to be other-than-temporarily impaired. The Company estimates fair value of its cost method investment considering available information such as pricing in recent rounds of financing, current cash positions, earnings and cash flow forecasts, recent operational performance and any other readily available market data, which represents level 3 in the fair value hierarchy. As of September 30, 2017 , the Company determined there were no other-than-temporary impairments on its cost method investment. Fair value measurement The Company's financial assets that are included in cash and cash equivalents and that are measured at fair value on a recurring basis consisted of $144.4 million and $106.3 million at September 30, 2017 and December 31, 2016 , respectively, and were invested in treasury money market funds. The fair value of the treasury money market funds is determined based on quoted market prices, which represents level 1 in the fair value hierarchy as defined by Accounting Standard Codification ("ASC") 820, " Fair Value Measurement and Disclosure ." The Company's short-term investments that are measured at fair value are comprised of zero and $10.0 million invested in available-for-sale commercial paper as of September 30, 2017 and December 31, 2016 , respectively, and zero and $6.0 million invested in certificate of deposit at September 30, 2017 and December 31, 2016 , respectively. The fair value of these accounts is determined based on quoted market prices for similar assets in active markets, which represents level 2 in the fair value hierarchy. The Company recorded an immaterial amount of unrealized gain related to the short-term investments for the three and nine months ended September 30, 2017 and 2016 . Reclassification adjustments for realized gain (loss) on available-for-sale securities in net income were immaterial for the three and nine months ended September 30, 2017 and 2016 . Deferred revenue and unbilled receivables Software license and implementation services that have been performed, but for which the Company has not invoiced the customer, are recorded as unbilled receivables, and invoices that have been issued before the software license and implementation, maintenance and subscription services have been performed are recorded as deferred revenue in the accompanying unaudited condensed consolidated balance sheets. Credit facility On January 27, 2017, the Company, through its wholly owned subsidiary PROS, Inc., entered into a Seventh Amendment (the "Seventh Amendment") to the $50 million secured Credit Agreement ("Revolver"). The Seventh Amendment provides for, among other things, an extension of the maturity date of the Revolver to July 2, 2022, and additional financial covenants with which the Company must comply if the Company's liquidity falls below an increased amount of $50 million or upon the occurrence of an event of default. The remaining material terms of the Revolver remain unchanged, and are summarized in the Company's Annual Report, Note 14. As of September 30, 2017 , the Company had no outstanding borrowings under the Revolver, and $0.2 million of unamortized debt issuance costs related to the Revolver is included in prepaid and other current assets and other long-term assets in the condensed consolidated balance sheets. For the three and nine months ended September 30, 2017 and 2016 , the Company recorded an immaterial amount of amortization of debt issuance cost which is included in other expense, net in the unaudited condensed consolidated statements of comprehensive income (loss). Income taxes The Company recorded an income tax benefit of $0.3 million and tax provision of $0.2 million for the three months ended September 30, 2017 and 2016 , respectively, and tax provision of $0.1 million and $0.5 million for the nine months ended September 30, 2017 and 2016 , respectively, primarily related to foreign income taxes and state taxes not based on income. The effective tax rate for the three and nine months ended September 30, 2017 was 1% and 0% , respectively. The effective tax rate for both the three and nine months ended September 30, 2016 was (1)% . The income tax rates vary from the federal and state statutory rates primarily due to the valuation allowances on the Company’s deferred tax assets, the limitation on deductibility of certain officers’ compensation, and foreign and state taxes not based on income. During the three months ended September 30, 2017 , the Company recognized a deferred tax benefit due to the acquisition of Vayant Travel Technologies, Inc. The recorded deferred tax liability was driven by unamortizable intangible assets that required the company to release $0.5 million of valuation allowance. The Company estimates its annual effective tax rate at the end of each quarterly period. Jurisdictions with a projected loss for the year where no tax benefit can be recognized due to the valuation allowances on the Company’s deferred tax assets are excluded from the estimated annual effective tax rate. The impact of such an exclusion could result in a higher or lower effective tax rate during a particular quarter depending on the mix and timing of actual earnings versus annual projections. Recently adopted accounting pronouncements In March 2016, the FASB issued ASU 2016-09, "Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting" which is intended to simplify several aspects of the accounting for share-based payment transactions including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This standard is effective for interim and annual reporting periods beginning after December 15, 2016. The Company adopted this standard on January 1, 2017. Upon adoption, the Company recognized the previously unrecognized excess tax benefits using the modified retrospective transition method, which resulted in a cumulative-effect adjustment of $4.2 million to accumulated deficit. The previously unrecognized excess tax effects were recorded as a deferred tax asset, which was fully offset by a valuation allowance and as such the cumulative adjustment had no net impact on the Company's financial statements. As required by ASU 2016-09, excess tax benefits recognized on stock-based compensation expense are reflected in the condensed consolidated statements of operations as a component of the provision for income taxes on a prospective basis. In addition, ASU 2016-09 allows companies to account for forfeitures as they occur or estimate expected forfeitures over the course of a vesting period; the Company has elected to continue to estimate forfeitures expected to occur to determine the amount of compensation cost to be recognized each period. Recent accounting pronouncements In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers (Top

Business Combination (Notes)

Business Combination (Notes)	9 Months Ended
	Sep. 30, 2017
Business Acquisition [Line Items]
Business Combination Disclosure [Text Block]	Business Combination On August 3, 2017, the Company acquired Vayant Travel Technologies, Inc. ("Vayant"), a privately held company based in Sofia, Bulgaria, for total cash consideration, net of cash acquired, of approximately $34.1 million . Vayant is a cloud software company that provides advanced shopping, merchandising and inspirational travel solutions. The acquisition of Vayant strengthens the Company's modern commerce solutions for the travel industry and positions it to deliver greater value to its travel customers through an end-to-end offer optimization solution designed to help travel companies deliver personalized offers and expanded choices that drive loyalty and growth. Since the acquisition date, the Company has included $1.3 million of revenue and $0.5 million of net loss related to Vayant in its consolidated income statement. During the quarter ended September 30, 2017 , the Company incurred acquisition-related costs of $0.6 million consisting primarily of advisory, legal fees, and retention of key employees. All of the assets acquired and the liabilities assumed in the transaction have been recognized at their acquisition date fair values at August 3, 2017. The preliminary allocation of the total purchase price for Vayant is as follows (in thousands): Cash $ 1,822 Other current assets 1,235 Noncurrent assets 86 Intangibles 18,600 Goodwill 17,052 Accounts payable and accrued liabilities (1,668 ) Deferred revenue (600 ) Deferred tax liability (526 ) Noncurrent liabilities (49 ) Net assets acquired $ 35,952 The following are the identifiable intangible assets acquired (in thousands) and their respective useful lives: Useful Life Amount (years) Developed technology $ 11,600 7 Customer relationships 7,000 5 Total $ 18,600 In performing the preliminary purchase price allocation, the Company considered, among other factors, its anticipated future use of the acquired assets, analysis of historical financial performance, and estimates of future cash flows from Vayant's products and services. The allocation resulted in acquired intangible assets of $18.6 million . The acquired intangible assets consisted of developed technology and customer relationships and were valued using the income approach in which the after-tax cash flows are discounted to present value. The cash flows are based on estimates used to price the transaction, and the discount rates applied were benchmarked with reference to the implied rate of return from the transaction model as well as the weighted average cost of capital. Additionally, the Company assumed certain liabilities in the acquisition, including deferred revenue to which a fair value of $0.6 million was ascribed using a cost-plus profit approach. The Company has made a preliminary determination that $0.5 million of net deferred tax liabilities were assumed on the acquisition date. The deferred tax liability is comprised of the value of intangible assets partially offset by a deferred tax asset related to net operating losses. The excess of the purchase price over the estimated amounts of net assets as of the effective date of the acquisition was allocated to goodwill. The factors contributing to the recognition of the amount of goodwill are based on several strategic and synergistic benefits that are expected to be realized from the Vayant acquisition. These benefits include the expectation that the combined company’s complementary products will strengthen the Company's modern commerce solutions for the travel industry. The Company believes the combined company will benefit from a broader global presence and, with the Company’s direct sales force and larger channel coverage, significant cross-selling opportunities. None of the goodwill is expected to be currently deductible for tax purposes. In accordance with applicable accounting standards, goodwill will not be amortized but instead will be tested for impairment at least annually, or more frequently if certain indicators are present. In the event that the management of the combined company determines that the value of goodwill has become impaired, the combined company will incur an accounting charge for the amount of the impairment during the fiscal quarter in which the determination is made. Pro Forma Financial Information The unaudited financial information in the table below summarizes the combined results of operations of the Company and Vayant, on a pro forma basis, as though the Company had acquired Vayant on January 1, 2016. The pro forma information for all periods presented also includes the effect of business combination accounting resulting from the acquisition, including amortization charges from acquired intangible assets. Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except earnings per share) 2017 2016 2017 2016 Total revenue $ 42,738 $ 40,316 $ 127,522 $ 118,770 Net loss (23,150 ) (17,081 ) (64,496 ) (61,815 ) Earnings per share - basic and diluted $ (0.73 ) $ (0.56 ) $ (2.05 ) $ (2.04 )

Earnings per Share (Note)

Earnings per Share (Note)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings per Share	Earnings per Share The following table sets forth the computation of basic and diluted earnings per share for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except per share data) 2017 2016 2017 2016 Numerator: Net loss $ (21,226 ) $ (15,708 ) $ (60,946 ) $ (56,712 ) Denominator: Weighted average shares (basic) 31,867 30,469 31,527 30,341 Dilutive effect of potential common shares — — — — Weighted average shares (diluted) 31,867 30,469 31,527 30,341 Basic loss per share $ (0.67 ) $ (0.52 ) $ (1.93 ) $ (1.87 ) Diluted loss per share $ (0.67 ) $ (0.52 ) $ (1.93 ) $ (1.87 ) Dilutive potential common shares consist of shares issuable upon the exercise of stock options, settlement of SARs, and the vesting of RSUs and MSUs. Potential common shares determined to be antidilutive and excluded from diluted weighted average shares outstanding were approximately 2.0 million and 2.0 million for the three months ended September 30, 2017 and 2016 , respectively, and 2.2 million and 1.9 million for the nine months ended September 30, 2017 and 2016 , respectively. Basic shares were used to calculate loss per share for the three and nine months ended September 30, 2017 and 2016 . Since the Company has the intention and ability to settle the principal amount of its Notes (see Note 5) in cash, the treasury stock method is expected to be used for calculating any potential dilutive effect of the conversion spread on diluted net income per share, if applicable. The conversion spread will have a dilutive impact on diluted net income per share of common stock when the average market price of common stock for a given period exceeds the conversion price of $33.79 and $48.63 per share, for the 2019 Notes and 2047 Notes, respectively.

Noncash Share-based Compensatio

Noncash Share-based Compensation (Note)	9 Months Ended
	Sep. 30, 2017
Noncash Share-based Compensation [Abstract]
Noncash Share-based Compensation	Noncash Share-based Compensation During the three months ended September 30, 2017 , the Company granted 10,788 RSUs with a weighted average grant-date fair value of $26.09 per share. The Company did not grant any MSUs, stock options and SARs during the three months ended September 30, 2017 . During the nine months ended September 30, 2017 , the Company granted 902,178 RSUs with a weighted average grant-date fair value of $21.43 per share. The Company also granted 110,100 MSUs with a weighted average grant-date fair value of $26.99 to certain executive employees during the nine months ended September 30, 2017 . These MSUs vest on March 1, 2020 and the actual number of MSUs that will be eligible to vest is based on the total stockholder return of the Company relative to the total stockholder return of the Index over the Performance Period, as defined by each award's plan documents or individual award agreements. The Company did not grant any stock options or SARs during the nine months ended September 30, 2017 . Share-based compensation expense is allocated to expense categories on the unaudited condensed consolidated statements of comprehensive income (loss). The following table summarizes share-based compensation expense included in the Company's unaudited condensed consolidated statements of comprehensive income (loss) for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Share-based compensation: Cost of revenue $ 479 $ 544 $ 1,569 $ 1,720 Operating expenses: Selling and marketing 909 (918 ) 3,313 2,559 General and administrative 2,864 2,235 8,546 6,267 Research and development 1,319 1,331 4,237 3,899 Total included in operating expenses 5,092 2,648 16,096 12,725 Total share-based compensation expense $ 5,571 $ 3,192 $ 17,665 $ 14,445 In January 2017, the number of shares available for issuance increased by 900,000 to 10,868,000 under an evergreen provision in the Company's 2007 Equity Incentive Plan ("2007 Stock Plan"). The 2007 Stock Plan expired on March 26, 2017. On March 24, 2017, the Board of Directors adopted the 2017 Equity Incentive Plan (2017 Stock Plan), and recommended that the Company’s stockholders approve the 2017 Stock Plan. The 2017 Stock Plan was approved by the stockholders in May 2017 and reserved an aggregate amount of 2,500,000 shares for issuance. As of September 30, 2017 , 2,489,212 shares remain available for issuance under the 2017 Stock Plan. At September 30, 2017 , the Company had an estimated $35.4 million of total unrecognized compensation costs related to share-based compensation arrangements. These costs will be recognized over a weighted average period of 2.4 years. The Company's Employee Stock Purchase Plan ("ESPP") provides for eligible employees to purchase shares on an after-tax basis in an amount between 1% and 10% of their annual pay: (i) on June 30 of each year at a 15% discount of the fair market value of the Company's common stock on January 1 or June 30, whichever is lower, and (ii) on December 31 of each year at a 15% discount of the fair market value of the Company's common stock on July 1 or December 31, whichever is lower. An employee may not purchase more than $5,000 in either of the six-month measurement periods described above or more than $10,000 annually. During the three and nine months ended September 30, 2017 , the Company issued 41,282 and 92,209 shares, respectively, under the ESPP. As of September 30, 2017 , 291,101 shares remain authorized and available for issuance under the ESPP. As of September 30, 2017 , the Company held approximately $0.5 million on behalf of employees for future purchases under the ESPP, and this amount was recorded in accrued liabilities in the Company's unaudited condensed consolidated balance sheet.

Convertible debt (Notes)

Convertible debt (Notes)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Long-term Debt [Text Block]	Convertible Debt The Company issued $143.8 million principal amount of convertible senior notes in December 2014 (the "2019 Notes") and $106.3 million principal amount of convertible senior notes in June 2017 (the "2047 Notes" and collectively with the 2019 Notes, the "Notes"). The interest rates for the Notes are fixed at 2.0% per annum. Interest is payable semi-annually in arrears on June 1 and December 1 of each year, commencing on June 1, 2015 for the 2019 Notes, and on December 1, 2017 for the 2047 Notes. The 2019 Notes mature on December 1, 2019, unless redeemed or converted in accordance with their terms prior to such date. The 2047 Notes mature on June 1, 2047, unless repurchased, redeemed or converted in accordance with their terms prior to such date. Each $1,000 of principal of the 2019 Notes will initially be convertible into 29.5972 shares of the Company’s common stock, which is equivalent to an initial conversion price of approximately $33.79 per share. Each $1,000 of principal amount at maturity of the 2047 Notes had an issue price of $880 , and will initially be convertible into 20.5624 shares of the Company’s common stock, which is equivalent to an initial conversion price of approximately $48.63 per share. The initial conversion price for each of the Notes is subject to adjustment upon the occurrence of certain specified events. An amount equal to the difference between the issue price and the principal amount at maturity will accrete to the 2047 Notes in accordance with the schedule set forth in the 2047 Notes. The issue price plus such accreted amount of the 2047 Notes is referred to herein as the “accreted principal amount.” On June 1, 2022, the accreted principal amount will accrete to 100% of the principal amount at maturity. The Notes are each general unsecured obligations and rank senior in right of payment to all of the Company's indebtedness that is expressly subordinated in right of payment to the Notes, rank equally in right of payment with all of the Company's existing and future liabilities that are not so subordinated, are effectively junior to any of the Company's secured indebtedness to the extent of the value of the assets securing such indebtedness and are structurally subordinated to all indebtedness and other liabilities (including trade payables but excluding intercompany obligations owed to the Company or its subsidiaries). On or after September 1, 2019 to the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert all or any portion of their 2019 Notes regardless of the contingent conversion conditions described herein. Upon conversion, the Company will pay or deliver cash, shares of its common stock or a combination of cash and shares of its common stock, at its election, as described in the indenture governing the 2019 Notes. On or before June 1, 2021, and subject to the satisfaction of certain conditions, the Company is entitled to elect to redeem all or any portion of the 2047 Notes at a redemption price equal to 100% of the accreted principal amount of the 2047 Notes, plus accrued and unpaid interest to, but excluding, the redemption date, if the daily volume weighted average price of the Company’s common stock is greater than or equal to 130% of the conversion price for at least 20 trading days during any 30 consecutive trading day period. After June 1, 2021, the Company will be entitled to elect to redeem all or any portion of the 2047 Notes (without regard to the price of the Company’s common stock) at a redemption price equal to the then current accreted principal amount of the 2047 Notes, plus accrued and unpaid interest to, but excluding, the redemption date. Holders may convert their 2019 Notes at their option at any time prior to the close of business on the business day immediately preceding September 1, 2019 only under the following circumstances: • during any calendar quarter commencing after the calendar quarter ending on March 31, 2015, if the last reported sale price of the common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; • during the five consecutive business day period immediately following any five consecutive trading day period in which the trading price per $1,000 principal amount of 2019 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company's common stock and the conversion rate on each such trading day; or • upon the occurrence of specified corporate events. Holders may convert their 2047 Notes at their option on any day prior to the close of business on the business day immediately preceding March 1, 2047 under the following circumstances: • during any calendar quarter commencing after the calendar quarter ending September 30, 2017, if the last reported sale price of the Company's common stock for 20 or more trading days (whether or not consecutive) in a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter exceeds 130% of the applicable conversion price in effect on each such trading day; • during the five consecutive business day period immediately following any five consecutive trading day period (the "Measurement Period") in which the trading price per 2047 Note for each day of that Measurement Period was less than 98% of the product of the last reported sale price of the Company's common stock and the conversion rate on each such day; or • upon the occurrence of specified corporate events. The 2047 Notes will also be convertible, regardless of the foregoing circumstances, at any time from, and including, March 1, 2047 until the close of business on the second scheduled trading day immediately preceding the applicable maturity date. Each holder of the 2047 Notes has the right to require the Company to repurchase for cash all or any portion of such holder's 2047 Notes on June 1, 2022 at a price per $1,000 principal amount of the 2047 Notes equal to the accreted principal amount at maturity plus accrued and unpaid interest to, but excluding, the repurchase date. If a fundamental change (as defined in the relevant indenture governing the applicable series of Notes) occurs prior to the maturity date, holders of each of the 2019 Notes and 2047 Notes may require the Company to repurchase all or a portion of their notes for cash at a repurchase price equal to 100% of the principal amount at maturity of the Notes, plus any accrued and unpaid interest to, but excluding, the repurchase date. If such a fundamental change occurs prior to June 1, 2022, holders of the 2047 Notes may also require the Company to repurchase all or a portion of their notes for cash at a repurchase price equal to the then current accreted principal amount of the Notes, plus any accrued and unpaid interest to, but excluding, the repurchase date. In addition, if specific corporate events occur prior to the applicable maturity date, the Company will be required to increase the conversion rate for holders who elect to convert their notes in certain circumstances. Holders who convert their 2047 Notes in connection with a Make-Whole Fundamental Change (as defined in the indenture governing the 2047 Notes) or in connection with a redemption of such 2047 Notes on or prior to June 1, 2021 will, under certain circumstances, be entitled to a make-whole premium in the form of an increase in the conversion rate determined by reference to a make-whole table set forth in such indenture. As of September 30, 2017 , the 2019 Notes and the 2047 Notes are not yet convertible. In accordance with accounting guidance on embedded conversion features, the Company valued and bifurcated the conversion options associated with each of the 2019 Notes and 2047 Notes from the respective host debt instrument, which is referred to as debt discount and recorded the conversion option of each of the Notes in stockholders’ equity. The equity component for each Note is not remeasured as long as such Note continues to meet the conditions for equity classification. In accounting for the transaction costs for each of the notes issuance, the Company allocated the costs incurred to the liability and equity components in proportion to the allocation of the proceeds from issuance to the liability and equity components. Issuance costs attributable to the liability component, totaling $4.3 million for the 2019 Notes and $2.7 million for the 2047 Notes, are being amortized to expense over the expected life of each notes using the effective interest method. Issuance costs attributable to the equity component related to the conversion option, totaling $1.2 million for the 2019 Notes and $0.3 million for the 2047 Notes, were netted with the equity component in stockholders' equity. As of September 30, 2017 , no cash payments were made for the debt issuance cost related to the 2047 Notes. The Notes consist of the following (in thousands): September 30, 2017 December 31, 2016 Liability component: Principal $ 250,000 $ 143,750 Less: debt discount and issuance cost, net of amortization (39,688 ) (21,451 ) Net carrying amount $ 210,312 $ 122,299 Equity component (1) $ 37,560 $ 28,714 (1) Recorded within additional paid-in capital in the consolidated balance sheet. As of September 30, 2017 , it included $28.7 million and $8.8 million related to the 2019 Notes and the 2047 Notes, respectively, net of $1.2 million and $0.3 million issuance cost in equity, respectively. The following table sets forth total interest expense recognized related to the Notes (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 2.0% coupon $ 1,250 $ 719 $ 2,741 $ 2,157 Amortization of debt issuance costs 340 209 782 620 Amortization of debt discount 2,504 1,411 5,555 4,166 Total $ 4,094 $ 2,339 $ 9,078 $ 6,943 As of September 30, 2017 and December 31, 2016 , the fair value of the principal amount of the Notes was $239.7 million and $141.1 million , respectively. The estimated fair value was determined based on inputs that are observable in the market or that could be derived from, or corroborated with, observable market data, including the Company's stock price and interest rates, which represents level 2 in the fair value hierarchy. As of September 30, 2017 , the remaining life of the 2019 Notes and the 2047 Notes is approximately 26 months and 56 months, respectively. Note Hedge and Warrant Transactions Concurrently with the offering of the 2019 Notes, the Company entered into separate convertible note hedge (the "Note Hedge") and warrant (the "Warrant") transactions. Taken together, the purchase of the Note Hedge and the sale of the Warrant are intended to offset any actual dilution from the conversion of the 2019 Notes and to effectively increase the overall conversion price of the 2019 Notes from $33.79 to $45.48 per share. The total cost of the Note Hedge transaction was $29.4 million . The Company received $17.1 million in cash proceeds from the sale of the Warrant. Pursuant to the Warrants, if the average market value per share of the Company's common stock for the reporting period, as measured under the Warrant, exceeds the strike price of the Warrant, the Warrant will have a dilutive effect on the Company's earnings per share. Holders of the 2019 Notes and Note Hedge will not have any rights with respect to the Warrant, as the Note Hedge is not part of the 2019 Notes or the Warrant. The Warrant is not part of the 2019 Notes or Note Hedge. Both the Note Hedge and Warrant have been accounted for as part of additional paid-in capital.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation In the ordinary course of business, the Company regularly becomes involved in contract and other negotiations and, in more limited circumstances, becomes involved in legal proceedings, claims and litigation. The outcomes of these matters are inherently unpredictable. The Company is not currently involved in any outstanding litigation that it believes, individually or in the aggregate, will have a material adverse effect on its business, financial condition, results of operations or cash flows. Purchase commitments In the ordinary course of business, the Company enters in various purchase commitments for goods and services. In June 2017, the Company entered in a noncancelable agreement with a computing infrastructure vendor that expires on June 30, 2020. The purchase commitment as of September 30, 2017 was $19.7 million for the remaining period under the three-year agreement. Lease commitments The Company leases office space and office equipment under noncancelable operating leases that expire at various dates. As a result of the Vayant acquisition, the Company assumed an operating lease in Sofia, Bulgaria for office space that expires in early 2018. In August 2017, the Company entered into a new operating lease in Sofia to replace the expiring Sofia lease. As of September 30, 2017 , the future minimum lease commitments related to lease agreements were as follows: Year Ending December 31, Amount Remaining 2017 $ 569 2018 3,553 2019 2,923 2020 1,443 2021 957 2022 and thereafter 718 Total minimum lease payments $ 10,163

Summary of Significant Accoun13

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with generally accepted accounting principles in the United States ("GAAP") for interim financial reporting and applicable quarterly reporting regulations of the Securities and Exchange Commission ("SEC"). In management's opinion, the accompanying interim unaudited condensed consolidated financial statements include all adjustments necessary for a fair statement of the financial position of the Company as of September 30, 2017 , the results of operations for the three and nine months ended September 30, 2017 and 2016 , and cash flows for the nine months ended September 30, 2017 and 2016 . Certain information and disclosures normally included in the notes to the annual financial statements prepared in accordance with GAAP have been omitted from these interim unaudited condensed consolidated financial statements pursuant to the rules and regulations of the SEC. Accordingly, these unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2016 ("Annual Report") filed with the SEC. The condensed consolidated balance sheet as of December 31, 2016 was derived from the Company's audited consolidated financial statements but does not include all disclosures required under GAAP.
Basis of consolidation	Basis of consolidation The unaudited condensed consolidated financial statements include the accounts of the Company, its wholly owned subsidiaries and a subsidiary where the Company exercises control. All intercompany transactions and balances have been eliminated in consolidation. The functional currency of PROS France SAS, formerly known as Cameleon Software SA ("PROS France") is the Euro. The financial statements of this subsidiary are translated into U.S. dollars using period-end rates of exchange for assets and liabilities, historical rates of exchange for equity, and average rates of exchange for the period for revenue and expenses. Translation gains (losses) are recorded in accumulated other comprehensive loss as a component of stockholders' equity.
Dollar amounts	Dollar amounts The dollar amounts presented in the tabular data within these footnote disclosures are stated in thousands of dollars, except per share amounts, or as noted within the context of each footnote disclosure.
Use of estimates	Use of estimates The Company makes estimates and assumptions in the preparation of its unaudited condensed consolidated financial statements, and its estimates and assumptions may affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated financial statements, and the reported amounts of revenue and expenses during the reporting periods. Actual results could differ from those estimates. The complexity and judgment required in the Company's estimation process, as well as issues related to the assumptions, risks and uncertainties inherent in the application of the percentage-of-completion method of accounting, affect the amounts of revenue, expenses, unbilled receivables and deferred revenue. Estimates are also used for, but not limited to, receivables, allowance for doubtful accounts, useful lives of assets, depreciation and amortization, income taxes and deferred tax asset valuation, valuation of stock options, other current liabilities and accrued liabilities. Numerous internal and external factors can affect estimates. The critical accounting policies related to the estimates and judgments are discussed in the Company's Annual Report under management's discussion and analysis of financial condition and results of operations. There have been no significant changes to the Company's critical accounting policies as described in the Company's Annual Report.
Revenue recognition	Revenue recognition The Company derives its revenues primarily from subscription services fees, professional services, the perpetual licensing of its software products and the associated software maintenance and support services. The Company commences revenue recognition when all of the following criteria are met: • there is persuasive evidence of an arrangement; • the service has been or is being provided to the customer; • collection of the fee is reasonably assured; and • the amount of fees to be paid by the customer is fixed and determinable. Subscription services revenue Subscription services revenue is generally recognized ratably over the contractual term of the arrangement beginning on the date that the Company's service is made available to the customer, assuming all other revenue recognition criteria have been met. The Company's subscription contracts do not provide customers with the right to take possession of the software supporting the applications and, as a result, are accounted for as service contracts. Any revenue related to up-front activation or set-up fees are deferred and recognized ratably over the estimated period that the customer benefits from the related services. Direct and incremental costs related to up-front activation or set-up activities are capitalized until the date the Company's service is made available and then expensed ratably over the estimated period that the customer benefits from the related services. For the Company's subscription services that include professional services, the Company determines whether the professional services have standalone value. Professional services deemed to have standalone value are accounted for separately from subscription services and the subscription services revenue recognition commences on the date that the Company's service is made available to the customer. If determined that the professional services do not have standalone value, the transaction is treated as a single element and the subscription services and professional services revenue is deferred until the customer commences use of the subscription services, and the subscription services revenue is recognized over the remaining term of the arrangement. Maintenance and support revenue Maintenance and support revenue includes post-implementation customer support and the right to unspecified software updates and enhancements on a when-and-if-available basis. The Company recognizes revenue from maintenance arrangements ratably over the period in which the services are provided. License revenue The Company derives the majority of its license revenue from the sale of perpetual licenses. For software license arrangements that do not require significant modification or customization of the underlying software, the Company recognizes software licenses revenues upon software delivery, assuming all other revenue recognition criteria have been met. The Company evaluates the nature and scope of professional services for each arrangement, and if it determines that the professional services revenue should not be accounted for separately from license revenue, the license revenue is recognized together with the professional services revenue using the percentage-of-completion method or completed contract method. The completed contract method is also used for contracts where there is a risk over final acceptance by the customer or for contracts that are short-term in nature. The percentage-of-completion method is measured by the percentage of man-days incurred during the reporting period as compared to the estimated total man-days necessary for each contract for implementation of the software solutions. The Company believes that for each such project, man-days expended in proportion to total estimated man-days at completion represents the most reliable and meaningful measure for determining a project's progress toward completion. Under the Company's fixed-fee arrangements, should a loss be anticipated on a contract, the full amount of the loss is recorded when the loss is determinable. The Company also licenses software solutions under term license agreements that typically include maintenance during the license term. When maintenance is included for the entire term of the term license, there is no renewal rate and the Company has not established vendor specific objective evidence ("VSOE") of fair value for the maintenance on term licenses. For term license agreements, revenue and the associated costs are deferred until the delivery of the solution and recognized ratably over the remaining license term. Professional services revenue Professional services revenues are generally recognized as the services are rendered for time and material contracts, or on a proportional performance basis for fixed price contracts. The majority of the Company's professional services contracts are on a time and materials basis. Training revenues are recognized as the services are rendered. For the Company's subscription services that include professional services, the Company determines whether the professional services have standalone value. Professional services deemed to have standalone value are accounted for separately from subscription services and typically recognized as the services are performed. If determined that the professional services do not have standalone value, the transaction is treated as a single element, the professional services revenue is deferred until the customer commences use of the subscription services, and the professional services revenue is recognized over the remaining term of the arrangement. For software license arrangements that include professional services, the Company determines whether the professional services are considered essential to the functionality of the software using factors such as: the nature of its software products; whether they are ready for use by the customer upon receipt; the nature of professional services; the availability of services from other vendors; whether the timing of payments for license revenue coincides with performance of services; and whether milestones or acceptance criteria exist that affect the realizability of the software license fee. For professional services considered essential to the functionality of the software, the license revenue is recognized together with the professional services revenue using the percentage-of-completion method or completed contract method. The completed contract method is also used for contracts where there is a risk over final acceptance by the customer or for contracts that are short-term in nature. Multiple element arrangements For arrangements with multiple deliverables, the Company evaluates whether the individual deliverables qualify as separate units of accounting. In order to treat deliverables in a multiple deliverable arrangement as separate units of accounting, the deliverables must have standalone value upon delivery. If the deliverables have standalone value upon delivery, the Company accounts for each deliverable separately and revenue is recognized for the respective deliverables as they are delivered. When multiple deliverables included in an arrangement are separable into different units of accounting, the arrangement consideration is allocated to the identified separate units of accounting based on their relative selling price. Multiple deliverable arrangement accounting guidance provides a hierarchy when determining the relative selling price for each unit of accounting. VSOE of selling price, based on the price at which the item is regularly sold by the vendor on a standalone basis, should be used if it exists. If VSOE of selling price is not available, third-party evidence ("TPE") of selling price is used to establish the selling price if it exists. If neither VSOE nor TPE exist for a deliverable, arrangements with multiple deliverables can be separated into discrete units of accounting based on the Company's best estimate of selling price ("BESP"). The objective of BESP is to determine the price at which the Company would transact a sale if the product or service were sold on a standalone basis. The amount of arrangement fee allocated is limited by contingent revenues, if any. For transactions that only include software and software-related elements, the Company continues to account for such arrangements under the software revenue recognition standards which require it to establish VSOE of fair value to allocate arrangement consideration to multiple deliverables. For multiple-element arrangements that contain software and nonsoftware elements such as its subscription services, the Company allocates revenue between the software and software related elements as a group and any nonsoftware elements based on a relative fair value allocation. The Company determines fair value for each deliverable using the selling price hierarchy described above and utilizing VSOE of fair value if it exists. The Company applies the residual method to recognize revenue for the delivered elements in standalone software transactions. Under the residual method, the amount of revenue allocated to delivered elements equals the total arrangement consideration, less the aggregate fair value of any undelivered elements, typically maintenance, provided that VSOE of fair value exists for all undelivered elements. VSOE of fair value is based on the price charged when the element is sold separately or, in the case of maintenance, substantive renewal rates for maintenance. Revenue that has been recognized, but for which the Company has not invoiced the customer, is recorded as unbilled receivables. Invoices that have been issued before revenue has been recognized are recorded as deferred revenue in the accompanying consolidated balance sheets.
Business Combinations Policy [Policy Text Block]	Business Combinations The Company records tangible and intangible assets acquired and liabilities assumed in business combinations under the acquisition method of accounting. Amounts paid for each acquisition are allocated to the assets acquired and liabilities assumed based on their fair values at the date of acquisition. Significant management judgments and assumptions are required in determining the fair value of acquired assets and liabilities, particularly acquired intangible assets. The valuation of purchased intangible assets is based upon estimates of the future performance and cash flows from the acquired business. Each asset is measured at fair value from the perspective of a market participant. The Company uses its best estimates and assumptions to accurately assign fair value to the tangible and intangible assets acquired and liabilities assumed at the acquisition date. The Company’s estimates are inherently uncertain and subject to refinement. During the measurement period, which may be up to one year from the acquisition date, the Company may record adjustments to the fair value of these tangible and intangible assets acquired and liabilities assumed, with the corresponding offset to goodwill. In addition, uncertain tax positions and tax-related valuation allowances are initially established in connection with a business combination as of the acquisition date. The Company continues to collect information and reevaluates these estimates and assumptions quarterly and records any adjustments to the Company’s preliminary estimates to goodwill, provided that the Company is within the measurement period. Upon the conclusion of the measurement period or final determination of the fair value of assets acquired or liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the Company’s condensed consolidated statements of operations.
Internal-use software	Internal-use software Costs incurred to develop internal-use software during the development stage are capitalized, stated at cost, and depreciated using the straight-line method over the estimated useful lives of the assets. Development stage costs generally include salaries and personnel costs and third-party contractor expenses associated with internal-use software configuration, coding, installation and testing. For the three months ended September 30, 2017 and 2016 , the Company capitalized $0.7 million and $0.5 million , respectively, and for the nine months ended September 30, 2017 and 2016 , the Company capitalized $2.2 million and $0.6 million , respectively, of internal-use software development costs related to cloud-based offerings. Capitalized internal-use software development costs related to cloud-based offerings are amortized using the straight-line method over the useful life of the asset. For the three and nine months ended September 30, 2017 , the Company amortized an immaterial amount of capitalized internal-use software development costs. For the three and nine months ended September 30, 2016 , the Company amortized no capitalized internal-use software development costs. Capitalized software for internal use is included in property and equipment, net in the unaudited condensed consolidated balance sheets. Amortization of capitalized internal-use software development costs, once it commences, is included in cost of subscription revenues in the accompanying unaudited condensed consolidated statements of comprehensive income (loss).
Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block]	Impairment of long-lived assets Long-lived assets are reviewed for impairment whenever an event or change in circumstances indicates that the carrying amount of an asset or group of assets may not be recoverable. The impairment review includes comparison of future cash flows expected to be generated by the asset or group of assets with the associated assets' carrying value. If the carrying value of the asset or group of assets exceeds its expected future cash flows (undiscounted and without interest charges), an impairment loss is recognized to the extent that the carrying amount of the asset exceeds its fair value. The Company recorded no impairment charges during the three and nine months ended September 30, 2017 and 2016 .
Noncash share-based compensation	Noncash share-based compensation The Company measures all share-based payments to its employees based on the grant date fair value of the awards and recognizes expenses in the Company's unaudited consolidated statement of comprehensive income (loss) on a straight-line basis over the periods during which the recipient is required to perform services (generally over the vesting period of the awards). To date, the Company has granted stock options, Restricted Stock Units ("RSUs"), stock settled Stock Appreciation Rights ("SARs"), and Market Stock Units ("MSUs"). RSUs include (i) time-based awards, and (ii) market-based awards in which the number of shares that vest are based upon attainment of target average per share closing price over a requisite trading period. MSUs are performance-based awards in which the number of shares that vest are based upon the Company's relative stockholder return. The following table presents the number of shares or units outstanding for each award type as of September 30, 2017 and December 31, 2016 , respectively, (in thousands): Award type September 30, 2017 December 31, 2016 Stock options 148 734 Restricted stock units (time-based) 2,180 2,237 Restricted stock units (market-based) 345 460 Stock appreciation rights 391 515 Market stock units 347 342 Stock options, time-based RSUs and SARs vest ratably between one and four years. Market-based RSUs vest if the average trailing closing price of the Company's Common Stock meets certain minimum performance hurdles for at least 105 calendar days prior to September 9, 2020, with 25% vesting at $27 , an additional 25% vesting at $33 , and the remaining 50% vesting at $41 . The actual number of MSUs that will be eligible to vest is based on the total stockholder return of the Company relative to the total stockholder return of the Russell 2000 Index ("Index") over their respective performance periods, as defined by each award's plan documents. The Company did not grant any stock options or SARs during the three and nine months ended September 30, 2017 or 2016 . The fair value of the time-based RSUs is based on the closing price of the Company's stock on the date of grant. The Company estimates the fair value and the derived service period of the market-based RSUs on the date of grant using a Monte Carlo simulation model. The model requires the use of a number of assumptions including the expected volatility of the Company's stock, its risk-free interest rate and expected dividends. The Company's expected volatility at the date of grant was based on the historical volatility of the Company over the performance period. The fair value of the market-based RSUs is expensed over the derived service period for each separate vesting tranche. The derived service period for the vesting tranches of the market-based RSUs ranges between 1.01 and 1.98 years. The Company estimates the fair value of MSUs on the date of grant using a Monte Carlo simulation model. The determination of fair value of the MSUs is affected by the Company's stock price and a number of assumptions including the expected volatilities of the Company's stock and the Index, its risk-free interest rate and expected dividends. The Company's expected volatility at the date of grant was based on the historical volatilities of the Company and the Index over the performance period. The weighted average assumptions used to value the MSUs granted during the three and nine months ended September 30, 2017 were as follows: September 30, 2017 Volatility 45.88% Risk-free interest rate 1.52% Expected option life in years 3.10 Dividend yield —
Earnings per share	Earnings per share The Company computes basic earnings (loss) per share by dividing net income (loss) attributable to common stockholders by the weighted average number of common shares outstanding. Diluted earnings (loss) per share is computed by dividing net income (loss) attributable to common stockholders by the weighted average number of common shares and dilutive potential common shares then outstanding. Diluted earnings per share reflect the assumed conversion of all dilutive securities, using the treasury stock method. Dilutive potential common shares consist of shares issuable upon the exercise of stock options, shares of unvested restricted stock units, and settlement of stock appreciation rights. When the Company incurs a net loss, the effect of the Company's outstanding stock options, stock appreciation rights and restricted stock units are not included in the calculation of diluted earnings (loss) per share as the effect would be anti-dilutive. Accordingly, basic and diluted net loss per share are identical.
Investment, Policy [Policy Text Block]	Short-term investments The Company's investments are available-for-sale commercial paper and certificate of deposit that are recorded at fair value in the consolidated balance sheets. The Company classifies all commercial paper regardless of original maturity at purchase date as investments. Unrealized gains and losses on available-for-sale securities are recorded, net of tax, as a component of accumulated other comprehensive income (loss), unless impairment is considered to be other-than-temporary. Other-than-temporary unrealized losses on available-for-sale securities are generally recorded in gain (loss) on investments, net, in the consolidated statements of comprehensive income (loss) unless certain criteria are met. The primary factors considered when determining if a charge must be recorded because a decline in the fair value of an investment is other-than-temporary include whether: (i) the fair value of the investment is significantly below the Company's cost basis; (ii) the financial condition of the issuer of the security has deteriorated; (iii) if a debt security, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the security; (iv) the decline in fair value has existed for an extended period of time; (v) if a debt security, such security has been downgraded by a rating agency; and (vi) the Company has the intent and ability to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value. Investments with remaining maturities of twelve months or less are classified as short-term investments since they are readily convertible to cash to fund short-term operations. Investments with remaining maturities of more than twelve months are classified as long-term investments. All of the Company's investments had contractual maturities of less than twelve months as of September 30, 2017 .
Cost Method Investments, Policy [Policy Text Block]	Cost method investment Investments in equity securities of privately held companies without readily determinable fair value, where the Company does not exercise significant influence over the investee, are recorded using the cost method of accounting, carrying the investment at historical cost. If there are no identified events or changes in circumstances that might have an adverse effect on the cost method investments, the Company does not estimate the investments' fair value. For all investments, if a decline in the fair value of an investment below the carrying value is determined to be other-than-temporary, such investment is written down to its estimated fair value with a charge to current earnings. At September 30, 2017 and December 31, 2016 , the Company held $2.0 million of equity securities in a privately held company. This investment is accounted for under the cost method and the Company measures it at fair value on a nonrecurring basis when it is deemed to be other-than-temporarily impaired. The Company estimates fair value of its cost method investment considering available information such as pricing in recent rounds of financing, current cash positions, earnings and cash flow forecasts, recent operational performance and any other readily available market data, which represents level 3 in the fair value hierarchy. As of September 30, 2017 , the Company determined there were no other-than-temporary impairments on its cost method investment.
Fair value measurement	Fair value measurement The Company's financial assets that are included in cash and cash equivalents and that are measured at fair value on a recurring basis consisted of $144.4 million and $106.3 million at September 30, 2017 and December 31, 2016 , respectively, and were invested in treasury money market funds. The fair value of the treasury money market funds is determined based on quoted market prices, which represents level 1 in the fair value hierarchy as defined by Accounting Standard Codification ("ASC") 820, " Fair Value Measurement and Disclosure ." The Company's short-term investments that are measured at fair value are comprised of zero and $10.0 million invested in available-for-sale commercial paper as of September 30, 2017 and December 31, 2016 , respectively, and zero and $6.0 million invested in certificate of deposit at September 30, 2017 and December 31, 2016 , respectively. The fair value of these accounts is determined based on quoted market prices for similar assets in active markets, which represents level 2 in the fair value hierarchy. The Company recorded an immaterial amount of unrealized gain related to the short-term investments for the three and nine months ended September 30, 2017 and 2016 . Reclassification adjustments for realized gain (loss) on available-for-sale securities in net income were immaterial for the three and nine months ended September 30, 2017 and 2016 .
Deferred Revenue and Unbilled Receivables [Policy Text Block]	Deferred revenue and unbilled receivables Software license and implementation services that have been performed, but for which the Company has not invoiced the customer, are recorded as unbilled receivables, and invoices that have been issued before the software license and implementation, maintenance and subscription services have been performed are recorded as deferred revenue in the accompanying unaudited condensed consolidated balance sheets.
Credit Facility	Credit facility On January 27, 2017, the Company, through its wholly owned subsidiary PROS, Inc., entered into a Seventh Amendment (the "Seventh Amendment") to the $50 million secured Credit Agreement ("Revolver"). The Seventh Amendment provides for, among other things, an extension of the maturity date of the Revolver to July 2, 2022, and additional financial covenants with which the Company must comply if the Company's liquidity falls below an increased amount of $50 million or upon the occurrence of an event of default. The remaining material terms of the Revolver remain unchanged, and are summarized in the Company's Annual Report, Note 14. As of September 30, 2017 , the Company had no outstanding borrowings under the Revolver, and $0.2 million of unamortized debt issuance costs related to the Revolver is included in prepaid and other current assets and other long-term assets in the condensed consolidated balance sheets. For the three and nine months ended September 30, 2017 and 2016 , the Company recorded an immaterial amount of amortization of debt issuance cost which is included in other expense, net in the unaudited condensed consolidated statements of comprehensive income (loss).
Income taxes	Income taxes The Company recorded an income tax benefit of $0.3 million and tax provision of $0.2 million for the three months ended September 30, 2017 and 2016 , respectively, and tax provision of $0.1 million and $0.5 million for the nine months ended September 30, 2017 and 2016 , respectively, primarily related to foreign income taxes and state taxes not based on income. The effective tax rate for the three and nine months ended September 30, 2017 was 1% and 0% , respectively. The effective tax rate for both the three and nine months ended September 30, 2016 was (1)% . The income tax rates vary from the federal and state statutory rates primarily due to the valuation allowances on the Company’s deferred tax assets, the limitation on deductibility of certain officers’ compensation, and foreign and state taxes not based on income. During the three months ended September 30, 2017 , the Company recognized a deferred tax benefit due to the acquisition of Vayant Travel Technologies, Inc. The recorded deferred tax liability was driven by unamortizable intangible assets that required the company to release $0.5 million of valuation allowance. The Company estimates its annual effective tax rate at the end of each quarterly period. Jurisdictions with a projected loss for the year where no tax benefit can be recognized due to the valuation allowances on the Company’s deferred tax assets are excluded from the estimated annual effective tax rate. The impact of such an exclusion could result in a higher or lower effective tax rate during a particular quarter depending on the mix and timing of actual earnings versus annual projections.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently adopted accounting pronouncements In March 2016, the FASB issued ASU 2016-09, "Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting" which is intended to simplify several aspects of the accounting for share-based payment transactions including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This standard is effective for interim and annual reporting periods beginning after December 15, 2016. The Company adopted this standard on January 1, 2017. Upon adoption, the Company recognized the previously unrecognized excess tax benefits using the modified retrospective transition method, which resulted in a cumulative-effect adjustment of $4.2 million to accumulated deficit. The previously unrecognized excess tax effects were recorded as a deferred tax asset, which was fully offset by a valuation allowance and as such the cumulative adjustment had no net impact on the Company's financial statements. As required by ASU 2016-09, excess tax benefits recognized on stock-based compensation expense are reflected in the condensed consolidated statements of operations as a component of the provision for income taxes on a prospective basis. In addition, ASU 2016-09 allows companies to account for forfeitures as they occur or estimate expected forfeitures over the course of a vesting period; the Company has elected to continue to estimate forfeitures expected to occur to determine the amount of compensation cost to be recognized each period. Recent accounting pronouncements In May 2014, the FASB issued ASU 2014-09, "Revenue from Contracts with Customers (Topic 606)," which supersedes nearly all existing revenue recognition guidance under GAAP and permits the use of either the retrospective or cumulative effect transition method. In August 2015, the FASB issued ASU 2015-14, "Revenue from Contracts with Customers: Deferral of the Effective Date" which deferred the effective date of the new revenue standard for periods beginning after December 15, 2016 to December 15, 2017, with early adoption permitted but not earlier than the original effective date. In March 2016, the FASB issued ASU 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations” which clarifies the implementation of guidance on principal versus agent considerations. In April 2016, the FASB issued ASU 2016-10, "Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligation and Licensing" which clarifies the implementation of guidance on identifying performance obligations and licensing. In May 2016, the FASB issued ASU 2016-12, "Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients", which clarifies the disclosure requirements for an entity that retrospectively applies the guidance in Topic 606. These standards are effective for the Company in the first quarter of fiscal 2018. The Company expects to adopt this updated standard on a modified retrospective basis and is currently evaluating the effect that the updated standard will have on its consolidated financial statements and related disclosures. The Company continues to assess all potential impacts of the new standard on its consolidated financial statements and related disclosures, and currently believes the most significant impact relates to its accounting for arrangements that include term-based software licenses bundled with maintenance and support, the deferral of incremental costs of obtaining a contract with a customer, including the period of amortization of such costs, and additional disclosures. Under current GAAP, the revenue attributable to these term-based software licenses is recognized ratably over the term of the arrangement because VSOE does not exist for the undelivered maintenance and support element as it is not sold separately. The requirement to have VSOE for undelivered elements to enable the separation of revenue for the delivered software licenses is eliminated under the new standard. Accordingly, under the new standard, the Company will be required to recognize as revenue a portion of the arrangement fee upon delivery of the software license. In addition, under current GAAP, the Company defers only direct and incremental commission costs to obtain a contract and amortizes those costs over the term of the related contract. Under the new standard, the Company will defer all incremental costs related to the customer contract and will amortize these costs over the expected period of customer benefit. While the Company currently expects revenue related to professional services and subscription services to remain substantially unchanged, it is still in the process of evaluating the impact of the new standard on these types of customer arrangements, including the impact of the deferral of incremental costs of obtaining a contract with a customer. In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)" which requires the lessee to recognize most leases on the balance sheet thereby resulting in the recognition of lease assets and liabilities for those leases currently classified as operating leases. Lessor accounting remains largely unchanged from current guidance, however, ASU 2016-02 provides improvements that are intended to align lessor accounting with the lessee model and with updated revenue recognition guidance. This standard is effective for interim and annual reporting periods beginning after December 15, 2018. The Company is currently assessing the impact of ASU 2016-02 on its condensed consolidated financial statements. In August 2016, the FASB issued ASU 2016-15, "Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments" which is intended to reduce the diversity in practice on classification of certain transactions in the statement of cash flows. This standard is effective for interim and annual reporting periods beginning after December 15, 2017; early adoption is permitted. The Company is currently assessing the impact of ASU 2016-15 on its condensed consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment", which eliminates step two from the goodwill impairment test. Under the amendments in this standard, an entity should recognize an impairment charge for the amount by which the carrying amount of a reporting unit exceeds its fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The standard is effective for interim and annual reporting periods beginning after December 15, 2019; earlier adoption is permitted for goodwill impairment tests performed on testing dates after January 1, 2017. The Company is currently assessing the impact of ASU 2017-04 on its condensed consolidated financial statements. With the exception of the new standards discussed above, there have been no other recent accounting pronouncements or changes in accounting pronouncements during the nine months ended September 30, 2017 , as compared to the recent accounting pronouncements described in the Company's Annual Report, that are of significance or potential significance to the Company.

Summary of Significant Accoun14

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Awards outstanding [Table Text Block]	The following table presents the number of shares or units outstanding for each award type as of September 30, 2017 and December 31, 2016 , respectively, (in thousands): Award type September 30, 2017 December 31, 2016 Stock options 148 734 Restricted stock units (time-based) 2,180 2,237 Restricted stock units (market-based) 345 460 Stock appreciation rights 391 515 Market stock units 347 342
Market Stock Units Valuation Assumptions [Table Text Block]	The weighted average assumptions used to value the MSUs granted during the three and nine months ended September 30, 2017 were as follows: September 30, 2017 Volatility 45.88% Risk-free interest rate 1.52% Expected option life in years 3.10 Dividend yield —

Business Combination (Tables)

Business Combination (Tables)	9 Months Ended
	Sep. 30, 2017
Business Acquisition [Line Items]
Business Combination, Schedule of purchase price allocation [Table Text Block]	The preliminary allocation of the total purchase price for Vayant is as follows (in thousands): Cash $ 1,822 Other current assets 1,235 Noncurrent assets 86 Intangibles 18,600 Goodwill 17,052 Accounts payable and accrued liabilities (1,668 ) Deferred revenue (600 ) Deferred tax liability (526 ) Noncurrent liabilities (49 ) Net assets acquired $ 35,952
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block]	The following are the identifiable intangible assets acquired (in thousands) and their respective useful lives: Useful Life Amount (years) Developed technology $ 11,600 7 Customer relationships 7,000 5 Total $ 18,600
Business Acquisition, Pro Forma Information [Table Text Block]	The unaudited financial information in the table below summarizes the combined results of operations of the Company and Vayant, on a pro forma basis, as though the Company had acquired Vayant on January 1, 2016. The pro forma information for all periods presented also includes the effect of business combination accounting resulting from the acquisition, including amortization charges from acquired intangible assets. Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except earnings per share) 2017 2016 2017 2016 Total revenue $ 42,738 $ 40,316 $ 127,522 $ 118,770 Net loss (23,150 ) (17,081 ) (64,496 ) (61,815 ) Earnings per share - basic and diluted $ (0.73 ) $ (0.56 ) $ (2.05 ) $ (2.04 )

Earnings per Share (Table)

Earnings per Share (Table)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following table sets forth the computation of basic and diluted earnings per share for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except per share data) 2017 2016 2017 2016 Numerator: Net loss $ (21,226 ) $ (15,708 ) $ (60,946 ) $ (56,712 ) Denominator: Weighted average shares (basic) 31,867 30,469 31,527 30,341 Dilutive effect of potential common shares — — — — Weighted average shares (diluted) 31,867 30,469 31,527 30,341 Basic loss per share $ (0.67 ) $ (0.52 ) $ (1.93 ) $ (1.87 ) Diluted loss per share $ (0.67 ) $ (0.52 ) $ (1.93 ) $ (1.87 )

Noncash Share-based Compensat17

Noncash Share-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2017
Noncash Share-based Compensation [Abstract]
Schedule of Share-based Compensation Expense	The following table summarizes share-based compensation expense included in the Company's unaudited condensed consolidated statements of comprehensive income (loss) for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Share-based compensation: Cost of revenue $ 479 $ 544 $ 1,569 $ 1,720 Operating expenses: Selling and marketing 909 (918 ) 3,313 2,559 General and administrative 2,864 2,235 8,546 6,267 Research and development 1,319 1,331 4,237 3,899 Total included in operating expenses 5,092 2,648 16,096 12,725 Total share-based compensation expense $ 5,571 $ 3,192 $ 17,665 $ 14,445

Convertible debt (Tables)

Convertible debt (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Convertible Debt [Table Text Block]	The Notes consist of the following (in thousands): September 30, 2017 December 31, 2016 Liability component: Principal $ 250,000 $ 143,750 Less: debt discount and issuance cost, net of amortization (39,688 ) (21,451 ) Net carrying amount $ 210,312 $ 122,299 Equity component (1) $ 37,560 $ 28,714 (1) Recorded within additional paid-in capital in the consolidated balance sheet. As of September 30, 2017 , it included $28.7 million and $8.8 million related to the 2019 Notes and the 2047 Notes, respectively, net of $1.2 million and $0.3 million issuance cost in equity, respectively. The following table sets forth total interest expense recognized related to the Notes (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 2.0% coupon $ 1,250 $ 719 $ 2,741 $ 2,157 Amortization of debt issuance costs 340 209 782 620 Amortization of debt discount 2,504 1,411 5,555 4,166 Total $ 4,094 $ 2,339 $ 9,078 $ 6,943

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2017
Future minimum lease commitments [Line Items]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	As of September 30, 2017 , the future minimum lease commitments related to lease agreements were as follows: Year Ending December 31, Amount Remaining 2017 $ 569 2018 3,553 2019 2,923 2020 1,443 2021 957 2022 and thereafter 718 Total minimum lease payments $ 10,163

Summary of Significant Accoun20

Summary of Significant Accounting Policies Significant Accounting Policies (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Summary of Significant Accounting Policies [Line Items]
Internal-use software development costs capitalized			$ 1,996,000	$ 569,000
Tangible Asset Impairment Charges			0
Treasury money market funds, at fair value	$ 144,400,000		144,400,000		$ 106,300,000
Commercial Paper	0		0		10,000,000
Deposits, Fair Value Disclosure	0		0		$ 6,000,000
Cost Method Investments, Fair Value Disclosure	2,000,000		2,000,000
Line of Credit Facility, Amount Outstanding	0		0
Line of Credit Facility, Maximum Borrowing Capacity	50,000,000		50,000,000
Debt Instrument, Covenant, Minimum Amount of Cash And Cash Equivalent	50,000,000		50,000,000
Unamortized Debt Issuance Expense	195,000		195,000
Income Tax Expense (Benefit)	$ (271,000)	$ 227,000	$ 55,000	$ 490,000
Effective income tax rate	1.00%		0.00%	(1.00%)
Valuation Allowances and Reserves, Deductions	$ 500,000
Cloud-based product offerings [Member]
Summary of Significant Accounting Policies [Line Items]
Internal-use software development costs capitalized	$ 748,000	$ 510,000	$ 2,170,000	$ 582,000
Capitalized Computer Software, Amortization			$ 0
Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period			1 year 4 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			1 year
Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period			1 year 11 months 23 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			4 years
Share-based Compensation Award, Tranche One [Member]
Summary of Significant Accounting Policies [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Awards vesting upon Price Target	25.00%		25.00%
Share Price Target	$ 27		$ 27
Share-based Compensation Award, Tranche Two [Member]
Summary of Significant Accounting Policies [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Awards vesting upon Price Target	25.00%		25.00%
Share Price Target	$ 33		$ 33
Share-based Compensation Award, Tranche Three [Member]
Summary of Significant Accounting Policies [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Awards vesting upon Price Target	50.00%		50.00%
Share Price Target	$ 41		$ 41

Summary of Significant Accoun21

Summary of Significant Accounting Policies Awards Outstanding (Details) - shares shares in Thousands	Sep. 30, 2017	Dec. 31, 2016
Stock options
Awards outstanding [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	148	734
Restricted Stock Units (RSUs) [Member]
Awards outstanding [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	2,180	2,237
Restricted stock unit - market-based [Member]
Awards outstanding [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	345	460
Stock appreciation rights
Awards outstanding [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	391	515
Market Share Units (MSUs) [Member]
Awards outstanding [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	347	342

Summary of Significant Accoun22

Summary of Significant Accounting Policies Fair Value Calculation Assumptions (Details) - Market Share Units (MSUs) [Member]	9 Months Ended
	Sep. 30, 2017
Valuation Assumptions for Stock Awards [Line Items]
Volatility	45.88%
Risk-free interest rate	1.52%
Expected life, in years	3 years 1 month 7 days
Dividend yield	0.00%

Summary of Significant Accoun23

Summary of Significant Accounting Policies New Accounting Pronouncements (Details) $ in Millions	Jan. 01, 2017USD ($)
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	$ 4.2

Business Combination (Details)

Business Combination (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Combination [Abstract]
Payments to Acquire Businesses, Net of Cash Acquired			$ 34,130	$ 0
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	$ 1,300
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	500
Business Combination, Acquisition Related Costs	$ 613	$ 0	$ 613	$ 0

Business Combination Business C

Business Combination Business Combination Pro Forma (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Business Combinations [Abstract]
Business Acquisition, Pro Forma Revenue	$ 42,738	$ 40,316	$ 127,522	$ 118,770
Business Acquisition, Pro Forma Net Income (Loss)	$ (23,150)	$ (17,081)	$ (64,496)	$ (61,815)
Business Acquisition, Pro Forma Earnings Per Share, Basic	$ (0.73)	$ (0.56)	$ (2.05)	$ (2.04)

Business Combination Business26

Business Combination Business Combination, Schedule Of Recognized Identified Assets Acquired And Liabilities Assumed (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Aug. 03, 2017	Dec. 31, 2016
Business Combinations [Abstract]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents		$ 1,822
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other		1,235
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets		86
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		18,600
Goodwill	$ 38,309	17,052	$ 20,096
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other		(1,668)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue		(600)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent		(526)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other		(49)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net		$ 35,952

Business Combination Business27

Business Combination Business Combination, Schedule of Finite-Lived Intangible Assets Acquired (Details) $ in Thousands	Aug. 03, 2017USD ($)
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 18,600
Developed Technology Rights [Member]
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired	$ 11,600
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	7 years
Customer Relationships [Member]
Business Acquisition [Line Items]
Finite-lived Intangible Assets Acquired	$ 7,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years

Earnings per Share (Details)

Earnings per Share (Details) - $ / shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive potential common shares excluded from computation of earnings per share	1,990	1,961	2,163	1,907
Notes due 2019 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt Instrument, Convertible, Stock Price Trigger			$ 33.79
Notes due 2047 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt Instrument, Convertible, Stock Price Trigger			$ 48.63

Earnings per Share Basis and Di

Earnings per Share Basis and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator
Net income (loss)	$ (21,226)	$ (15,708)	$ (60,946)	$ (56,712)
Denominator
Weighted average shares (basic)	31,867,000	30,469,000	31,527,000	30,341,000
Dilutive effect of potential common shares	0	0	0	0
Weighted average shares (diluted)	31,867,000	30,469,000	31,527,000	30,341,000
Basic Earnings Per Share	$ (0.67)	$ (0.52)	$ (1.93)	$ (1.87)
Diluted earnings per share	$ (0.67)	$ (0.52)	$ (1.93)	$ (1.87)

Noncash Share-based Compensat30

Noncash Share-based Compensation (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2017USD ($)$ / sharesshares	Sep. 30, 2017USD ($)$ / sharesshares
Noncash Share-based Compensation (Narrative) [Line Items]
Unrecognized compensation cost related to share-based compensation | $	$ 35,440,000	$ 35,440,000
Weighted average period to recognize cost, in years		2 years 4 months 20 days
Share-based compensation arrangement by share-based payment, Minimum Employee Subscription rate		1.00%
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate	10.00%	10.00%
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Offering Date		15.00%
Maximum Amount Contributable by employees under ESPP- Half yearly | $		$ 5,000
Maximum Amount Contributable By Employees Under ESPP- Annually | $		$ 10,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans	41,282	92,209
ESPP contributions by Employees | $		$ 526,000
RSUs
Noncash Share-based Compensation (Narrative) [Line Items]
Awards, other than options, granted in period	10,788	902,178
Weighted average grant date fair value, per share, of awards granted in period | $ / shares	$ 26.09	$ 21.43
MSUs
Noncash Share-based Compensation (Narrative) [Line Items]
Awards, other than options, granted in period		110,100
Weighted average grant date fair value, per share, of awards granted in period | $ / shares		$ 26.99
Employee Stock [Member]
Noncash Share-based Compensation (Narrative) [Line Items]
Shares available for future grants	291,101	291,101
2007 Equity Incentive Plan [Member]
Noncash Share-based Compensation (Narrative) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized		900,000
Shares reserved for issuance under Plan	10,868,000	10,868,000
2017 Equity Incentive Plan [Member] [Member]
Noncash Share-based Compensation (Narrative) [Line Items]
Shares reserved for issuance under Plan	2,500,000	2,500,000
Shares available for future grants	2,489,212	2,489,212
Share-based Compensation Award, Tranche One [Member]
Noncash Share-based Compensation (Narrative) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Awards vesting upon Price Target	25.00%	25.00%
Share Price Target | $ / shares	$ 27	$ 27
Share-based Compensation Award, Tranche Two [Member]
Noncash Share-based Compensation (Narrative) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Awards vesting upon Price Target	25.00%	25.00%
Share Price Target | $ / shares	$ 33	$ 33
Share-based Compensation Award, Tranche Three [Member]
Noncash Share-based Compensation (Narrative) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Awards vesting upon Price Target	50.00%	50.00%
Share Price Target | $ / shares	$ 41	$ 41

Noncash Share-based Compensat31

Noncash Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 5,571	$ 3,192	$ 17,665	$ 14,445
Cost of Sales [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	479	544	1,569	1,720
Selling and Marketing Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	909	(918)	3,313	2,559
General and Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	2,864	2,235	8,546	6,267
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	1,319	1,331	4,237	3,899
Operating Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 5,092	$ 2,648	$ 16,096	$ 12,725

Convertible debt (Details)

Convertible debt (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)$ / shares	Sep. 30, 2016USD ($)	Dec. 31, 2014USD ($)$ / shares	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	2.00%		2.00%
Debt Instrument, Face Amount	$ 250,000,000		$ 250,000,000			$ 143,750,000
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	39,688,000		39,688,000			21,451,000
Convertible Debt, Noncurrent	210,312,000		210,312,000			122,299,000
Debt Instrument, Convertible, Carrying Amount of Equity Component	37,560,000		37,560,000			28,714,000
Debt Instrument, Periodic Payment, Interest	1,250,000	$ 719,000	2,741,000	$ 2,157,000
Amortization of Financing Costs	340,000	209,000	782,000	620,000
Amortization of Debt Discount (Premium)	2,504,000	1,411,000	5,555,000	4,166,000
Interest Expense, Debt	4,094,000	$ 2,339,000	9,078,000	$ 6,943,000
Debt Instrument, Fair Value Disclosure	239,700,000		239,700,000			$ 141,062,000
Notes due 2047 [Member]
Debt Instrument [Line Items]
Debt Issuance Cost	2,700,000		2,700,000
Convertible debt, issuance cost, equity component			$ 300,000
Debt Instrument, Convertible, Conversion Ratio			20.5624
Debt Instrument, Convertible, Stock Price Trigger | $ / shares			$ 48.63
Debt instrument, Convertible, Initial issue price per $1,000 of principal	880		$ 880
Debt Instrument, Face Amount	106,250,000		106,250,000
Debt Instrument, Convertible, Carrying Amount of Equity Component	8,846,000		$ 8,846,000
Debt Instrument, Convertible, Remaining Discount Amortization Period			56 months
Notes due 2019 [Member]
Debt Instrument [Line Items]
Debt Issuance Cost	4,300,000		$ 4,300,000
Convertible debt, issuance cost, equity component			$ 1,200,000
Debt Instrument, Convertible, Conversion Ratio			29.5972
Debt Instrument, Convertible, Stock Price Trigger | $ / shares			$ 33.79
Debt Instrument, Face Amount	143,750,000		$ 143,750,000
Debt Instrument, Convertible, Carrying Amount of Equity Component	$ 28,714,000		$ 28,714,000
Debt Instrument, Convertible, Remaining Discount Amortization Period			26 months
Purchase of convertible bond hedge					$ (29,411,000)
Investment Warrants, Exercise Price | $ / shares					$ 45.48
Proceeds from Issuance of Warrants					$ 17,106,000

Commitments and Contingencies F

Commitments and Contingencies Future minimum lease payments (Details) $ in Thousands	Sep. 30, 2017USD ($)
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Due, Remainder of Fiscal Year	$ 569
Operating Leases, Future Minimum Payments, Due in Two Years	3,553
Operating Leases, Future Minimum Payments, Due in Three Years	2,923
Operating Leases, Future Minimum Payments, Due in Four Years	1,443
Operating Leases, Future Minimum Payments, Due in Five Years	957
Operating Leases, Future Minimum Payments, Due Thereafter	718
Operating Leases, Future Minimum Payments Due	$ 10,163

Commitments and Contingencies P

Commitments and Contingencies Purchase commitments (Details) $ in Thousands	Sep. 30, 2017USD ($)
Long-term Purchase Commitment [Line Items]
Purchase Obligation	$ 19,700