PROS (PRO) 10-Q 25 Jul 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 22, 2019
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	001-33554
Entity Registrant Name	PROS HOLDINGS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	76-0168604
Entity Address, Address Line One	3100 Main Street, Suite 900
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77002
City Area Code	(713)
Local Phone Number	335-5151
Title of 12(b) Security	Common stock
Trading Symbol	PRO
Security Exchange Name	NYSE
Entity Central Index Key	0001392972
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		40,223,687

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 329,562	$ 295,476
Trade and other receivables, net of allowance of $977 and $978, respectively	53,069	41,822
Deferred Costs, Current	4,927	4,089
Prepaid and other current assets	7,692	4,756
Total current assets	395,250	346,143
Property and equipment, net	15,128	14,676
Operating Lease, Right-of-Use Asset	23,215	0
Deferred Costs, Noncurrent	14,468	13,373
Intangible Assets, Net (Excluding Goodwill)	15,845	19,354
Goodwill	38,161	38,231
Other long term assets, net	5,832	5,190
Total assets	507,899	436,967
Current liabilities:
Accounts payable	6,948	6,934
Accrued liabilities	13,314	9,506
Accrued payroll and other employee benefits	18,499	22,519
Operating Lease, Liability, Current	5,326	0
Deferred Revenue, Current	113,808	99,262
Convertible Debt, Current	21,121	136,529
Total current liabilities	179,016	274,750
Long-term deferred revenue	14,795	17,903
Convertible Debt, Noncurrent	198,428	88,661
Operating Lease, Liability, Noncurrent	19,415	0
Other Liabilities, Noncurrent	751	754
Total liabilities	412,405	382,068
Commitments and contingencies (see Note 9)
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; 44,601,308 and 41,573,491 shares issued, respectively; 40,183,723 and 37,155,906 shares outstanding, respectively	45	42
Additional paid-in capital	439,995	364,877
Treasury stock, 4,417,585 common shares, at cost	(13,938)	(13,938)
Retained Earnings (Accumulated Deficit)	(327,142)	(292,708)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(3,466)	(3,374)
Total stockholders' equity	95,494	54,899
Total liabilities and stockholders' equity	$ 507,899	$ 436,967

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Allowance for bad debts	$ 977,000	$ 978,000
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	44,601,308	41,573,491
Common stock - shares outstanding	40,183,723	37,155,906
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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Total subscription, maintenance and support revenue	$ 48,120	$ 38,263	$ 93,862	$ 75,787
Total revenue	63,878	47,426	120,009	95,336
Cost of Goods and Services Sold	23,583	18,724	44,373	38,245
Cost of subscription, maintenance and support	12,614	11,444	25,141	23,165
Gross profit	40,295	28,702	75,636	57,091
Operating Expenses
Selling and Marketing Expense	22,945	18,590	44,430	36,158
General and Administrative Expense	12,040	10,145	23,707	20,834
Research and development	17,455	12,960	33,254	27,744
Business Combination, Acquisition Related Costs	0	0	0	95
Income from operations	(12,145)	(12,993)	(25,755)	(27,740)
Other income (expense):
Convertible debt interest and amortization	(4,274)	(4,226)	(8,630)	(8,405)
Other Nonoperating Income (Expense)	(862)	244	409	446
Loss before income tax provision	(17,281)	(16,975)	(33,976)	(35,699)
Income tax provision (benefit)	236	(131)	458	1
Net income (loss)	$ (17,517)	$ (16,844)	$ (34,434)	$ (35,700)
Earnings Per Share, Basic	$ (0.44)	$ (0.52)	$ (0.89)	$ (1.10)
Net earnings (loss) per share:
Earnings Per Share, Basic and Diluted	(0.44)	(0.52)	(0.89)	(1.10)
Earnings Per Share, Diluted	$ (0.44)	$ (0.52)	$ (0.89)	$ (1.10)
Weighted average number of shares:
Weighted Average Number of Shares Outstanding, Basic and Diluted	39,413	32,651	38,518	32,514
Weighted Average Number of Shares Outstanding, Basic	39,413	32,651	38,518	32,514
Other comprehensive income, net of tax:
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	$ 178	$ (789)	$ (92)	$ (262)
Other comprehensive income	178	(789)	(92)	(262)
Comprehensive income (loss)	(17,339)	(17,633)	(34,526)	(35,962)
Subscription and Circulation [Member]
Revenue from Contract with Customer, Including Assessed Tax	33,080	22,038	63,495	42,988
Cost of Goods and Services Sold	9,779	8,491	19,504	17,255
Maintenance [Member]
Revenue from Contract with Customer, Including Assessed Tax	15,040	16,225	30,367	32,799
Cost of Goods and Services Sold	2,835	2,953	5,637	5,910
License [Member]
Revenue from Contract with Customer, Including Assessed Tax	2,028	695	2,534	1,761
Cost of Goods and Services Sold	40	64	101	137
Service [Member]
Revenue from Contract with Customer, Including Assessed Tax	13,730	8,468	23,613	17,788
Cost of Goods and Services Sold	$ 10,929	$ 7,216	$ 19,131	$ 14,943

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities:
Net income (loss)	$ (34,434)	$ (35,700)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, Depletion and Amortization	6,829	6,620
Amortization of Financing Costs and Discounts	6,295	5,929
Share-based compensation	12,025	11,398
Deferred Income Tax Expense (Benefit)	0	(252)
Provision for doubtful accounts	0	215
Loss on Disposition of Assets	0	37
Gain (Loss) on Extinguishment of Debt	2,266	0
Changes in operating assets and liabilities:
Accounts and unbilled receivables	(11,247)	(7,102)
Increase (Decrease) in Deferred Costs	(1,933)	(642)
Prepaid expenses and other assets	(3,523)	(62)
Accounts payable	(568)	1,729
Accrued liabilities	5,231	2,114
Accrued payroll and other employee benefits	(4,020)	(4,327)
Deferred revenue	11,435	11,733
Net cash provided by (used in) operating activities	(11,644)	(8,310)
Investing activities:
Purchases of property and equipment	(2,307)	(1,187)
Internal-use software development costs capitalized	(868)	(2,484)
Payments to Acquire Other Investments	68	0
Payments to Acquire Intangible Assets	50	0
Net cash provided by (used in) investing activities	(3,293)	(3,671)
Financing activities:
Exercise of stock options	0	1,201
Proceeds from Stock Plans	943	834
Tax withholding related to net share settlement of restricted stock units	(18,642)	(8,968)
Repayments of Notes Payable	0	(55)
Proceeds from Convertible Debt	140,156	0
Payments of Debt Issuance Costs	(648)	0
Purchase of capped call	16,445	0
Payment for Debt Extinguishment or Debt Prepayment Cost	(75,958)	0
Proceeds from bond hedge termination	64,819	0
Payment for warrant termination	(45,243)	0
Net cash provided by (used in) financing activities	48,982	(6,988)
Effect of Exchange Rate on Cash and Cash Equivalents	41	331
Net change in cash and cash equivalents	34,086	(18,638)
Cash and cash equivalents:
Beginning of period	295,476	160,505
End of period	329,562	141,867
Capital Expenditures Incurred but Not yet Paid	$ 922	$ 22

Condensed Consolidated Statem_3

Condensed Consolidated Statement of Stockholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income, net of tax [Member]
Common Stock, Shares, Outstanding, Beginning Balance at Dec. 31, 2017		31,939,175
Stockholders' Equity Attributable to Parent at Dec. 31, 2017	$ (46,979)	$ 36	$ 207,924	$ (13,938)	$ (238,185)	$ (2,816)
Treasury Stock, Shares - Beginning Balance at Dec. 31, 2017				4,417,585
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, New Issues		159,557
Proceeds from Stock Options Exercised	1,201		1,201
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		575,492
Stock Issued During Period, Value, Restricted Stock Award, Gross	(8,968)	$ 1	(8,969)
Stock Issued During Period, Shares, Employee Stock Purchase Plans		37,115
Proceeds from Stock Plans	834		834
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	11,491		11,491
Cumulative effect of adoption of section 606	9,724				9,724
Other Comprehensive Income (Loss), Net of Tax	(262)					(262)
Net Income (Loss) Attributable to Parent	(35,700)				(35,700)
Treasury Stock, Shares - Enging Balance at Jun. 30, 2018				4,417,585
Stockholders' Equity Attributable to Parent at Jun. 30, 2018	(68,659)	$ 37	212,481	$ (13,938)	(264,161)	(3,078)
Common Stock, Shares, Outstanding, Ending Balance at Jun. 30, 2018		32,711,339
Common Stock, Shares, Outstanding, Beginning Balance at Mar. 31, 2018		32,588,924
Stockholders' Equity Attributable to Parent at Mar. 31, 2018	(55,139)	$ 37	208,368	$ (13,938)	(247,317)	(2,289)
Treasury Stock, Shares - Beginning Balance at Mar. 31, 2018				4,417,585
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, New Issues		49,649
Proceeds from Stock Options Exercised	326		326
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		72,766
Stock Issued During Period, Value, Restricted Stock Award, Gross	(1,713)		(1,713)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	5,500		5,500
Other Comprehensive Income (Loss), Net of Tax	(789)					(789)
Net Income (Loss) Attributable to Parent	(16,844)				(16,844)
Treasury Stock, Shares - Enging Balance at Jun. 30, 2018				4,417,585
Stockholders' Equity Attributable to Parent at Jun. 30, 2018	$ (68,659)	$ 37	212,481	$ (13,938)	(264,161)	(3,078)
Common Stock, Shares, Outstanding, Ending Balance at Jun. 30, 2018		32,711,339
Common Stock, Shares, Outstanding, Beginning Balance at Dec. 31, 2018	37,155,906	37,155,906
Stockholders' Equity Attributable to Parent at Dec. 31, 2018	$ 54,899	$ 42	364,877	$ (13,938)	(292,708)	(3,374)
Treasury Stock, Shares - Beginning Balance at Dec. 31, 2018	4,417,585			4,417,585
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Proceeds from Stock Options Exercised	$ 0
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		815,976
Stock Issued During Period, Value, Restricted Stock Award, Gross	$ (18,642)	$ 1	(18,643)
Stock Issued During Period, Shares, Employee Stock Purchase Plans	35,340	35,340
Proceeds from Stock Plans	$ 943		943
Stock Issued During Period, Shares, Conversion of Convertible Securities	2,180,000	2,176,501
Stock Issued During Period, Value, Conversion of Convertible Securities	$ 44,811	$ 2	44,809
Adjustment to additional paid in capital, termination of bond hedge and warrant	64,819		64,819
Adjustment to additional paid in capital, termination of warrant	(45,243)		(45,243)
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	32,883		32,883
Adjustments to Additional Paid in Capital, Other	(16,445)		(16,445)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	11,995		11,995
Other Comprehensive Income (Loss), Net of Tax	(92)					(92)
Net Income (Loss) Attributable to Parent	$ (34,434)				(34,434)
Treasury Stock, Shares - Enging Balance at Jun. 30, 2019	4,417,585			4,417,585
Stockholders' Equity Attributable to Parent at Jun. 30, 2019	$ 95,494	$ 45	439,995	$ (13,938)	(327,142)	(3,466)
Common Stock, Shares, Outstanding, Ending Balance at Jun. 30, 2019	40,183,723	40,183,723
Common Stock, Shares, Outstanding, Beginning Balance at Mar. 31, 2019		37,872,661
Stockholders' Equity Attributable to Parent at Mar. 31, 2019	$ 30,470	$ 42	357,635	$ (13,938)	(309,625)	(3,644)
Treasury Stock, Shares - Beginning Balance at Mar. 31, 2019				4,417,585
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		134,561
Stock Issued During Period, Value, Restricted Stock Award, Gross	$ (4,403)	$ 1	(4,404)
Stock Issued During Period, Shares, Employee Stock Purchase Plans	0
Stock Issued During Period, Shares, Conversion of Convertible Securities		2,176,501
Stock Issued During Period, Value, Conversion of Convertible Securities	$ 44,811	$ 2	44,809
Adjustment to additional paid in capital, termination of bond hedge and warrant	64,819		64,819
Adjustment to additional paid in capital, termination of warrant	(45,243)		(45,243)
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt	32,883		32,883
Adjustments to Additional Paid in Capital, Other	(16,445)		(16,445)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	5,941		5,941
Other Comprehensive Income (Loss), Net of Tax	178					178
Net Income (Loss) Attributable to Parent	$ (17,517)				(17,517)
Treasury Stock, Shares - Enging Balance at Jun. 30, 2019	4,417,585			4,417,585
Stockholders' Equity Attributable to Parent at Jun. 30, 2019	$ 95,494	$ 45	$ 439,995	$ (13,938)	$ (327,142)	$ (3,466)
Common Stock, Shares, Outstanding, Ending Balance at Jun. 30, 2019	40,183,723	40,183,723

Organization and Nature of Oper

Organization and Nature of Operations	6 Months Ended
	Jun. 30, 2019
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"), provides artificial intelligence ("AI") solutions that power commerce in the digital economy by providing fast, frictionless and personalized buying experiences. PROS solutions enable dynamic buying experiences for both business-to-business ("B2B") and business-to-consumer ("B2C") companies across industry verticals. Companies can use the Company's dynamic pricing optimization, sales effectiveness, revenue management and commerce solutions to assess their market environments in real time to deliver customized prices and offers. The Company's solutions enable buyers to move fluidly across its customers’ direct sales, online, mobile and partner channels with personalized experiences regardless of which channel those customers choose. The Company's decades of data science and AI expertise are infused into its solutions and are designed to reduce time and complexity through actionable intelligence. The Company provides standard configurations of its software based on the industries it serves and offers professional services to configure these solutions to meet the specific needs of each customer.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Notes)	6 Months Ended
	Jun. 30, 2019
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 unaudited 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 June 30, 2019 , the results of operations for the three and six months ended June 30, 2019 and 2018 , cash flows for the six months ended June 30, 2019 and 2018 , and stockholders' equity for the three and six months ended June 30, 2019 and 2018 . 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, 2018 ("Annual Report") filed with the SEC. The unaudited condensed consolidated balance sheet as of December 31, 2018 was derived from the Company's audited consolidated financial statements but does not include all disclosures required under GAAP. Changes in accounting policies The Company has consistently applied these accounting policies to all periods presented in these consolidated financial statements, except for the Company's adoption of certain accounting standards described in more detail under " Recently adopted accounting pronouncements " in this Note 2 below. 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 ("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 determining the nature and timing of satisfaction of performance obligations and determining the standalone selling price of performance obligations, 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, operating lease right-of-use assets and operating lease liabilities, 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 estimates and judgments are discussed in the Annual Report under management's discussion and analysis of financial condition and results of operations and are also discussed under Item 2 "Management's discussion and analysis of financial condition and results of operations ". Revenue recognition The Company derives its revenues primarily from subscription services, professional services, perpetual licensing of its software products and associated software maintenance and support services. The Company determines revenue recognition through the following steps: • Identification of the contract, or contracts, with a customer; • Identification of the performance obligations in the customer contract(s); • Determination of the transaction price; • Allocation of the transaction price to each performance obligation in the customer contract(s); and • Recognition of revenue when, or as, the Company satisfies a performance obligation. Subscription services revenue Subscription services primarily include customer access to one or more of the Company's cloud applications and associated customer support. Subscription services revenue is generally recognized ratably over the contractual subscription term, beginning on the date that the Company's subscription service is made available to the customer. The Company's subscription contracts do not provide customers with the right to take possession of the software supporting the service and, as a result, are accounted for as service contracts. The Company's subscription contracts are generally two to five years in length, billed annually in advance, and non-cancelable. Maintenance and support revenue Maintenance and support revenue includes post-implementation customer support for on-premise licenses and the right to unspecified software updates and enhancements. The Company recognizes revenue from maintenance and support arrangements ratably over the period in which the services are provided. The Company's maintenance and support contracts are generally one to three years in length, billed annually in advance, and non-cancelable. License revenue Licenses to on-premise software provide the customer with a right to use, in the customer's environment, the Company's software as it exists when made available to the customer. License revenue from customer contracts with distinct on-premises licenses is recognized at the point in time when the software is made available to the customer. For customer contracts that contain license and professional services that are not considered distinct, both the license and professional services are determined to be a single performance obligation and the revenue is recognized over time based upon the Company's efforts to satisfy the performance obligation. Professional services revenue Professional services revenue primarily consists of fees for deployment and configuration services, as well as training services. Professional services revenues are generally recognized as the services are rendered for time and material contracts, or on a proportional performance basis for fixed fee contracts. The majority of the Company's professional services contracts are on a fixed fee basis. Training revenues are recognized as the services are rendered. Significant judgment is required in determining whether professional services contained in a customer subscription services contract are capable of being distinct and are separately identifiable in the customer contract. Professional services determined to be distinct are accounted for as a separate performance obligation and revenue is recognized as the services are performed. If the professional services are not determined to be distinct, the professional services and the subscription services are accounted for as a single performance obligation and revenue is recognized over the contractual term of the subscription beginning on the date that subscription services are made available to the customer. Customer contracts with multiple performance obligations A portion of the Company's customer contracts contain multiple performance obligations. Significant judgment is required in determining whether multiple performance obligations contained in a single customer contract are capable of being distinct and are separately identifiable. An obligation determined to be distinct is accounted for as a separate performance obligation and revenue for that separate performance obligation is recognized when, or as, the Company satisfies the performance obligation. If obligations are not determined to be distinct, those obligations are accounted for as a single, combined performance obligation. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use ("ROU") assets, current operating lease liabilities and noncurrent operating lease liabilities in the Company's unaudited condensed consolidated balance sheet. ROU assets represent the Company’s right to use an underlying asset over the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the lease commencement date based on the estimated present value of lease payments over the lease term. The Company includes any anticipated lease incentives in the determination of lease liability. The Company uses its estimated incremental borrowing rate, which is derived from information available at the lease commencement date, in determining the present value of lease payments. The Company gives consideration to its recent debt issuances as well as publicly available data for instruments with similar characteristics when determining its incremental borrowing rates. The Company’s lease terms will include options to extend the lease when it is reasonably certain that the Company will exercise that option. Leases with a term of 12 months or less are not recorded on the Company's unaudited condensed consolidated balance sheet. The Company’s lease agreements do not contain any residual value guarantees. Internal-use software Costs incurred to develop internal-use software during the development stage are capitalized, stated at cost, and amortized 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 June 30, 2019 and 2018 , the Company capitalized zero and $1.1 million , respectively, of internal-use software development costs related to cloud-based offerings, and for the six months ended June 30, 2019 and 2018 , the Company capitalized $0.9 million and $2.5 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 months ended June 30, 2019 and 2018 , the Company amortized $0.8 million and $0.2 million , respectively, and for the six months ended June 30, 2019 and 2018 , the Company amortized $1.3 million and $0.3 million , respectively, of 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 and cost of services 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 six months ended June 30, 2019 and 2018 . 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, (ii) performance-based awards in which the number of shares that vest are based upon achievement of certain internal performance metrics set by the Company, and (iii) 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 June 30, 2019 and December 31, 2018 , respectively, (in thousands): Award type June 30, 2019 December 31, 2018 Restricted stock units (time-based) 1,876 1,969 Restricted stock units (performance-based) 114 — Restricted stock units (market-based) — 215 Stock appreciation rights 282 287 Market stock units 267 419 Stock options, time-based RSUs and SARs vest ratably between one and 4 years . Performance-based RSUs vest on the third anniversary of the grant and the maximum number of shares issuable upon vesting is 200% of the initially granted shares based upon achievement of certain internal performance metrics set by the Company, as defined by each award's plan documents or individual award agreements. 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, SARs or MSUs during the three and six months ended June 30, 2019 or 2018 . The fair value of the time-based and performance-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. 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 giving effect to all dilutive potential common shares outstanding during the period using the treasury stock method and convertible notes using the if-converted method. Dilutive potential common shares consist of shares issuable upon the exercise of stock options, shares of unvested restricted stock units and market 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, restricted stock units, market stock units and convertible notes 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. Equity 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 at cost, less impairment and adjusted for subsequent observable price changes obtained from orderly transactions for identical or similar investments issued by the same investee. Adjustments resulting from impairment, fair value, or observable price changes are accounted for in the unaudited condensed consolidated statements of comprehensive income (loss). As of June 30, 2019 and December 31, 2018 , the Company held $2.1 million and $2.0 million , respectively, of equity securities in a privately held company. This investment is accounted for at cost, less impairment and adjusted for subsequent observable price changes obtained from orderly transactions for identical or similar investments issued by the same investee. The Company estimates fair value of its equity 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 defined by Accounting Standard Codification ("ASC") 820, " Fair Value Measurement and Disclosure " ("ASC 820"). As of June 30, 2019 and December 31, 2018 , the Company determined there were no other-than-temporary impairments on its equity 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 $294.8 million and $268.6 million at June 30, 2019 and December 31, 2018 , 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 ASC 820. Trade and other receivables Trade and other receivables are primarily comprised of trade receivables, net of allowance for doubtful accounts, contract assets and unbilled receivables. The Company records trade accounts receivable for its unconditional rights to consideration arising from the Company's performance under contracts with customers. The Company's standard billing terms are that payment is due upon receipt of invoice, payable generally within thirty to sixty days. The carrying value of such receivables, net of the allowance for doubtful accounts, represents their estimated net realizable value. The Company estimates its allowance for doubtful accounts for specific trade receivable balances based on historical collection trends, the age of outstanding trade receivables, existing economic conditions, and any financial security associated with the receivables. Contract assets represent conditional rights to consideration that have been recognized as revenue in advance of billing the customer. Unbilled receivables represent unconditional rights to consideration arising from contingent revenue that have been recognized as revenue in advance of billing the customer. Deferred costs Sales commissions earned by the Company's sales representatives are considered incremental and recoverable costs of obtaining a customer contract. Sales commissions are deferred and amortized on a straight-line basis over the period of benefit, which the Company has determined to be five to eight years. The Company determined the period of benefit by taking into consideration its customer contracts, expected renewals of those customer contracts (as the Company currently does not pay an incremental sales commission), the Company's technology and other factors. The Company also defers amounts earned by employees other than sales representatives who earn incentive payments under compensation plans that are also tied to the value of customer contracts acquired. Deferred costs were $19.4 million and $17.5 million as of June 30, 2019 and December 31, 2018 , respectively. Amortization expense for the deferred costs was $1.1 million and $0.7 million for the three months ended June 30, 2019 and 2018 , respectively, and $2.2 million and $1.4 million for the six months ended June 30, 2019 and 2018 , respectively. Deferred implementation costs The Company capitalizes certain contract fulfillment costs, including personnel and other costs (such as hosting, employee salaries, benefits and payroll taxes), that are associated with arrangements where professional services are not distinct from other undelivered obligations in its customer contracts. The Company analyzes implementation costs and capitalizes those costs that are directly related to customer contracts, that are expected to be recoverable, and that enhance the resources which will be used to satisfy the undelivered performance obligations in those contracts. Deferred implementation costs are amortized ratably over the remaining contract term once the revenue recognition criteria for the respective performance obligation has been met and revenue recognition commences. Deferred implementation costs were $4.7 million and $3.9 million as of June 30, 2019 and December 31, 2018 , respectively. Amortization expense for the deferred implementation costs was $0.4 million and $0.1 million for the three months ended June 30, 2019 and 2018 , respectively, and $0.6 million and $0.2 million for the six months ended June 30, 2019 and 2018 , respectively. Deferred implementation costs are included in prepaid and other current assets and other assets, noncurrent in the unaudited condensed consolidated balance sheets. Amortization of deferred implementation costs is included in cost of subscription and cost of services revenues in the accompanying unaudited condensed consolidated statements of comprehensive income (loss). Deferred revenue Deferred revenue primarily consists of customer invoicing in advance of revenues being recognized. The Company generally invoices its customers annually in advance for subscription services and maintenance and support services. Deferred revenue that is anticipated to be recognized during the next twelve-month period is recorded as current deferred revenue and the remaining portion is recorded as long-term. Credit facility As of June 30, 2019 , the Company had no outstanding borrowings under its $50.0 million secured Credit Agreement ("Revolver") with the lenders party thereto and Wells Fargo Bank, National Association as agent for the lenders party thereto. The Company included $0.1 million of unamortized debt issuance costs related to the Revolver in prepaid and other current assets and other assets, noncurrent in the unaudited condensed consolidated balance sheets. For the three and six months ended June 30, 2019 and 2018 , the Company recorded an immaterial amount of amortization of debt issuance cost which is included in other income (expense), net in the unaudited condensed consolidated statements of comprehensive income (loss). Income taxes The Company recorded an income tax provision of $0.2 million and tax benefit of $0.1 million for the three months ended June 30, 2019 and 2018 , respectively, and a tax provision of $0.5 million and zero for the six months ended June 30, 2019 and 2018 , respectively, primarily related to foreign income taxes and withholding taxes. The effective tax rate was (1.4)% and 0.8% for the three months ended June 30, 2019 and 2018 , respectively, and (1.3)% and 0.0% for the six months ended June 30, 2019 and 2018 , respectively. 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 and foreign and state taxes not based on income. 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 February 2016, the FASB issued ASU 2016-02, " Leases (Topic 842) " ("Topic 842"), which requires the lessee to recognize most leases on the balance sheet thereby resulting in the recognition of right-of-use ("ROU") assets and lease liabilities for those leases currently classified as operating leases. Lessor accounting remains largely unchanged from current guidance, however, Topic 842 provides improvements that are intended to align lessor accounting with the lessee model and with updated revenue recognition guidance. This standard took effect in the first quarter of 2019, including interim periods within that reporting period. The Company adopted Topic 842 as of January 1, 2019 using the modified retrospective method by recognizing the cumulative effect of initially applying the new standard as an adjustment to the opening balances of operating ROU assets and lease liabilities, while prior period amounts are not adjusted and continue to be reported in accordance with the Company's historic accounting under the prior lease accounting rules in ASC 840, " Leases ". The Company elected the package of practical expedients permitted under the transition guidance within the new Topic 842 standard for all asset classes, which among other things, allowed the Company to carryforward the historical lease classification. The Company also elected the hindsight practical expedient to determine the reasonably certain lease term for existing leases. The Company made an accounting policy election to not recognize leases with an initial term of 12 months or less on the balance sheet and instead would recognize those lease payments on a straight-line basis over the lease term in the unaudited condensed consolidated statement of comprehensive income (loss). The adoption of the standard had a material impact on the Company’s unaudited condensed consolidated balance sheet as a result of the increase of $26.9 million in assets and liabilities from recognition of ROU assets and lease liabilities. The standard did not have a material impact on the Company's unaudited condensed consolidated statement of comprehensive income (loss). In August 2018, the FASB issued ASU 2018-15, "Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract" ("Subtopic 350-40") . The amendment aligns the requirements for capitalizing implementation costs in a cloud computing arrangement service contract with the requirements for capitalizing implementation costs incurred to develop or obtain an internal-use software. The standard is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019; early adoption is permitted. The Company early adopted Subtopic 350-40 prospectively effective January 1, 2019 and there was no impact on the Company's unaudited condensed consolidated financial statements as of the adoption date. In addition, the new standard had no significant impact on the unaudited condensed consolidated financial statements for the three and six months ended June 30, 2019 . Recently issued accounting pronouncements not yet adopted In January 2017, the FASB issued ASU 2017-04, " Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment " ("Topic 350"), 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 after January 1, 2017. The Company is currently assessing the impact of Topic 350 on its unaudited 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 six months ended June 30, 2019 , as compared to the recent accounting pronouncements described in the Company's Annual Report, that are of significance or potential significance to the Company.

Deferred Revenue and Performanc

Deferred Revenue and Performance Obligation (Notes)	6 Months Ended
	Jun. 30, 2019
Deferred Revenue and Performance Obligation [Abstract]
Deferred revenue and performance obligation [Text Block]	Deferred Revenue and Performance Obligations Deferred Revenue For the three months ended June 30, 2019 and 2018 , the Company recognized approximately $43.7 million and $33.0 million , respectively, and for the six months ended June 30, 2019 and 2018 , the Company recognized approximately $67.1 million and $51.7 million , respectively, in each case of revenue that was included in the deferred revenue balances at the beginning of the respective periods and primarily related to subscription services, maintenance and support, and services. Performance Obligations As of June 30, 2019 , the Company expects to recognize approximately $378.0 million of revenue from remaining performance obligations. The Company expects to recognize revenue on approximately $182.7 million of these performance obligations over the next 12 months, with the balance recognized thereafter.

Disaggregation of Revenue (Note

Disaggregation of Revenue (Notes)	6 Months Ended
	Jun. 30, 2019
Disaggregation of Revenue [Abstract]
Disaggregation of Revenue [Text Block]	Disaggregation of Revenue Revenue by Geography The geographic information in the table below is presented for the three and six months ended June 30, 2019 and 2018 . The Company categorizes geographic revenues based on the location of the customer's headquarters. Because the Company's contracts are predominately denominated in U.S. dollars, it has limited exposure to foreign currency exchange risk as discussed under " Foreign Currency Exchange Risk " of Part I, Item 3 below. Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Revenue Percent Revenue Percent Revenue Percent Revenue Percent United States of America $ 20,862 33 % $ 16,566 35 % $ 40,642 34 % $ 33,928 35 % Europe 18,720 29 % 14,808 31 % 36,007 30 % 30,091 32 % The rest of the world 24,296 38 % 16,052 34 % 43,360 36 % 31,317 33 % Total revenue $ 63,878 100 % $ 47,426 100 % $ 120,009 100 % $ 95,336 100 %

Leases (Notes)

Leases (Notes)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lessee, Operating Leases [Text Block]	Leases The Company has operating leases for data centers, computer infrastructure, corporate offices and certain equipment. These leases have remaining lease terms ranging from 1 year to 14 years . Some of these leases include options to extend for up to 15 years, and some include options to terminate within 1 year. As of June 30, 2019 , the Company did not have any finance leases. The components of operating lease expense were as follows (in thousands): Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 Operating lease cost $ 2,244 $ 4,493 Variable lease cost 588 891 Sublease income (132 ) (149 ) Total lease cost $ 2,700 $ 5,235 Supplemental information related to leases was as follows (in thousands): Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 Cash paid for amounts included in the measurement of lease liability: Operating cash flows from operating leases $ 1,866 $ 2,882 June 30, 2019 Weighted average remaining lease term: Operating leases 8.1 years Weighted average discount rate: Operating leases 7.65 % As of June 30, 2019 , maturities of lease liabilities were as follows (in thousands): Year Ending December 31, Amount Remaining 2019 $ 3,262 2020 5,184 2021 6,030 2022 4,588 2023 4,604 2024 and thereafter 38,716 Total operating lease payments 62,384 Less: Imputed interest (23,437 ) Less: Anticipated lease incentive (14,207 ) Total operating lease liabilities $ 24,740 As of June 30, 2019 , the Company has additional operating leases of approximately $1.5 million that have not yet commenced, as the lessor has not made the underlying assets available for use by the Company. These operating leases will commence in fiscal year 2019 with lease terms of 5 years to 14 years . As of December 31, 2018, the future minimum lease commitments related to lease agreements under Topic 840, the predecessor of Topic 842, were as follows: Year Ending December 31, Amount 2019 $ 4,164 2020 1,649 2021 5,115 2022 6,181 2023 5,679 2024 and thereafter 57,365 Total minimum lease payments $ 80,153

Earnings per Share (Note)

Earnings per Share (Note)	6 Months Ended
	Jun. 30, 2019
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 six months ended June 30, 2019 and 2018 : Three Months Ended June 30, Six Months Ended June 30, (in thousands, except per share data) 2019 2018 2019 2018 Numerator: Net loss $ (17,517 ) $ (16,844 ) $ (34,434 ) $ (35,700 ) Denominator: Weighted average shares (basic) 39,413 32,651 38,518 32,514 Dilutive effect of potential common shares — — — — Weighted average shares (diluted) 39,413 32,651 38,518 32,514 Basic loss per share $ (0.44 ) $ (0.52 ) $ (0.89 ) $ (1.10 ) Diluted loss per share $ (0.44 ) $ (0.52 ) $ (0.89 ) $ (1.10 ) 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 2.1 million for the three months ended June 30, 2019 and 2018 , respectively, and 2.0 million and 2.1 million for the six months ended June 30, 2019 and 2018 , respectively. Potential common shares related to the convertible notes determined to be antidilutive and excluded from diluted weighted average shares outstanding were 4.8 million for the three and six months ended June 30, 2019 .

Noncash Share-based Compensatio

Noncash Share-based Compensation (Note)	6 Months Ended
	Jun. 30, 2019
Noncash Share-based Compensation [Abstract]
Noncash Share-based Compensation	Noncash Share-based Compensation During the three months ended June 30, 2019 , the Company granted 3,643 RSUs with a weighted average grant-date fair value of $52.15 per share. The Company granted no MSUs, options or SARs during this period. During the six months ended June 30, 2019 , the Company granted 739,459 RSUs (time-based) with a weighted average grant-date fair value of $33.23 per share. The Company also granted 113,919 performance-based RSUs ("PRSUs") with a weighted average grant-date fair value of $33.05 to certain executive employees during the six months ended June 30, 2019 . These PRSUs vest on January 15, 2022 and the actual number of PRSUs that will be eligible to vest is based upon achievement of certain internal performance metrics, as defined by each award's plan documents or individual award agreements. The maximum number of shares issuable upon vesting is 200% of the PRSUs initially granted. The Company did not grant any stock options, SARs or MSUs during the six months ended June 30, 2019 . 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 six months ended June 30, 2019 and 2018 : Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Share-based compensation: Cost of revenue $ 494 $ 398 $ 1,032 $ 880 Operating expenses: Selling and marketing 1,414 1,284 2,814 2,568 General and administrative 2,808 2,688 5,620 5,567 Research and development 1,263 1,092 2,559 2,383 Total included in operating expenses 5,485 5,064 10,993 10,518 Total share-based compensation expense $ 5,979 $ 5,462 $ 12,025 $ 11,398 The Company's 2017 Equity Incentive Plan (as amended and restated, the "2017 Stock Plan") was approved by stockholders in May 2017 and reserved an aggregate amount of 2,500,000 shares for issuance. In May 2019, the shareholders approved an amendment to the 2017 Stock Plan which increased the aggregate amount of shares for issuance to a total of 4,550,000 . As of June 30, 2019 , 2,523,987 shares remain available for issuance under the 2017 Stock Plan. At June 30, 2019 , the Company had an estimated $51.5 million of total unrecognized compensation costs related to share-based compensation arrangements. These costs will be recognized over a weighted average period of 2.7 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 six months ended June 30, 2019 , the Company issued zero and 35,340 shares, respectively, under the ESPP. As of June 30, 2019 , 180,215 shares remain authorized and available for issuance under the ESPP. As of June 30, 2019 , the Company held approximately $1.1 million on behalf of employees for future purchases under the ESPP, and this amount was recorded in accrued payroll and other employee benefits in the Company's unaudited condensed consolidated balance sheet.

Convertible debt (Notes)

Convertible debt (Notes)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Long-term Debt [Text Block]	Convertible Senior Notes The following is a summary of the Company's convertible senior notes as of June 30, 2019 (in thousands): Date of Issuance Unpaid Principal Balance Net Carrying Amount Contractual Interest Rates Current Noncurrent 2% Convertible Senior Note due in 2019 ("2019 Notes") December 2014 $ 21,606 $ 21,121 — 2% 2% Convertible Senior Notes due in 2047 ("2047 Notes") June 2017 $ 106,250 — $ 91,061 2% 1% Convertible Notes due in 2024 ("2024 Notes") May 2019 $ 143,750 $ — $ 107,367 1% In May 2019, the Company issued the 2024 Notes in an aggregate principal amount of 143.8 million . The interest rate for the 2024 Notes is fixed at 1% per annum. Interest is payable semi-annually in arrears on May 15 and November 15 of each year, commencing on November 15, 2019. The 2024 Notes mature on May 15, 2024, unless redeemed or converted in accordance with their terms prior to such date. Each $1,000 of principal of the 2024 Notes will initially be convertible into 15.1394 shares of the Company’s common stock, which is equivalent to an initial conversion price of approximately $66.05 per share. The initial conversion price for the 2024 Notes is subject to adjustment upon the occurrence of certain specified events. On or after February 15, 2024 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 2024 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 2024 Notes. Holders may convert their 2024 Notes at their option at any time prior to the close of business on the business day immediately preceding February 15, 2024 only under the following circumstances: • during the five consecutive business day period immediately following any five consecutive trading day period (the "Measurement Period") in which the trading price per 2024 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; • during any calendar quarter commencing after the calendar quarter ending on June 30, 2019, if the last reported sale price of the 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 is greater than or equal to 130% of the conversion price on each applicable trading day; or • upon the occurrence of specified corporate events. The 2019 Notes, the 2024 Notes and 2047 Notes (collectively, the "Notes") are 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). As of June 30, 2019 , the Notes are not yet convertible. As of June 30, 2019 , the remaining term of the Notes is approximately 5 months , 58 months and 35 months , respectively. As of June 30, 2019 and December 31, 2018 , the fair value of the principal amount of the Notes was $350.5 million and $251.5 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. 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, $3.4 million for the 2024 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, $1.1 million for the 2024 Notes and $0.3 million for the 2047 Notes, were netted with the equity component in stockholders' equity. In May 2019, the Company used a portion of the net proceeds of the offering of the 2024 Notes to exchange and retire $122.1 million in aggregate principal of the 2019 Notes for an aggregate cash consideration of $76.0 million and approximately 2.18 million shares of the Company's common stock (the "Exchange Transactions"). The Company recorded a $2.3 million loss on debt extinguishment related to the Exchange Transactions. The loss on extinguishment is included in the other (expense) income, net in the the accompanying unaudited condensed consolidated statements of comprehensive income (loss). The Notes consist of the following (in thousands): June 30, 2019 December 31, 2018 Liability component: Principal $ 271,606 $ 250,000 Less: debt discount and issuance cost, net of amortization (52,057 ) (24,810 ) Net carrying amount $ 219,549 $ 225,190 Equity component (1) $ 70,443 $ 37,560 (1) Recorded within additional paid-in capital in the consolidated balance sheet. As of June 30, 2019 , it included $28.7 million , $32.9 million and $8.8 million related to the 2019 Notes, the 2024 Notes and the 2047 Notes, respectively, which was net of $1.2 million , $1.1 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Coupon interest $ 1,106 $ 1,250 $ 2,356 $ 2,500 Amortization of debt issuance costs 341 352 706 701 Amortization of debt discount 2,827 2,624 5,568 5,204 Total $ 4,274 $ 4,226 $ 8,630 $ 8,405 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. 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. In May 2019, in connection with the Exchange Transactions, the Company entered into certain note hedge termination agreements (the “Note Hedge Termination Agreements”) and warrant termination agreements (the “Warrant Termination Agreements”). The Company received cash proceeds of $64.8 million related to the Note Hedge Termination Agreements and paid $45.2 million related to the Warrant Termination Agreements. The Note Hedge Termination Agreements terminated certain of the Note Hedges that were entered into by the Company in connection with the offering of the 2019 Notes. The Warrant Termination Agreements terminated certain of the Warrants that were entered into by the Company in connection with the offering of the 2019 Notes. Capped Call Transactions In May 2019, in connection with the offering of the 2024 Notes, the Company entered into privately negotiated capped call transactions (collectively, the "Capped Call") with certain option counterparties. The Capped Call transactions cover, subject to customary anti-dilution adjustments, the number of shares of the Company’s common stock initially underlying the 2024 Notes, at a strike price that corresponds to the initial conversion price of the 2024 Notes, also subject to adjustment, and are exercisable upon conversion of the 2024 Notes. The Capped Call transactions are intended to reduce potential dilution of the Company's common stock and/or offset any cash payments the Company will be required to make in excess of the principal amount upon any conversion of 2024 Notes, and to effectively increase the overall conversion price of the 2024 Notes from $66.05 to $101.62 per share. As the Capped Call transactions meet certain accounting criteria, they are recorded in stockholders’ equity and are not accounted for as derivatives. The cost of the Capped Call was $16.4 million and was recorded as part of additional paid-in capital.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
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 March 2019, the Company entered in a noncancelable agreement with a computing infrastructure vendor that amended the existing agreement dated June 2017. The amended agreement expires in March 2022. The purchase commitment as of June 30, 2019 was $68.5 million for the remaining period through the expiration of the agreement.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
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 June 30, 2019 , the results of operations for the three and six months ended June 30, 2019 and 2018 , cash flows for the six months ended June 30, 2019 and 2018 , and stockholders' equity for the three and six months ended June 30, 2019 and 2018 . 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, 2018 ("Annual Report") filed with the SEC. The unaudited condensed consolidated balance sheet as of December 31, 2018 was derived from the Company's audited consolidated financial statements but does not include all disclosures required under GAAP.
Accounting Changes [Text Block]	Changes in accounting policies The Company has consistently applied these accounting policies to all periods presented in these consolidated financial statements, except for the Company's adoption of certain accounting standards described in more detail under " Recently adopted accounting pronouncements " in this Note 2 below.
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 ("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 determining the nature and timing of satisfaction of performance obligations and determining the standalone selling price of performance obligations, 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, operating lease right-of-use assets and operating lease liabilities, 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 estimates and judgments are discussed in the Annual Report under management's discussion and analysis of financial condition and results of operations and are also discussed under Item 2 "Management's discussion and analysis of financial condition and results of operations ".
Revenue recognition	Revenue recognition The Company derives its revenues primarily from subscription services, professional services, perpetual licensing of its software products and associated software maintenance and support services. The Company determines revenue recognition through the following steps: • Identification of the contract, or contracts, with a customer; • Identification of the performance obligations in the customer contract(s); • Determination of the transaction price; • Allocation of the transaction price to each performance obligation in the customer contract(s); and • Recognition of revenue when, or as, the Company satisfies a performance obligation. Subscription services revenue Subscription services primarily include customer access to one or more of the Company's cloud applications and associated customer support. Subscription services revenue is generally recognized ratably over the contractual subscription term, beginning on the date that the Company's subscription service is made available to the customer. The Company's subscription contracts do not provide customers with the right to take possession of the software supporting the service and, as a result, are accounted for as service contracts. The Company's subscription contracts are generally two to five years in length, billed annually in advance, and non-cancelable. Maintenance and support revenue Maintenance and support revenue includes post-implementation customer support for on-premise licenses and the right to unspecified software updates and enhancements. The Company recognizes revenue from maintenance and support arrangements ratably over the period in which the services are provided. The Company's maintenance and support contracts are generally one to three years in length, billed annually in advance, and non-cancelable. License revenue Licenses to on-premise software provide the customer with a right to use, in the customer's environment, the Company's software as it exists when made available to the customer. License revenue from customer contracts with distinct on-premises licenses is recognized at the point in time when the software is made available to the customer. For customer contracts that contain license and professional services that are not considered distinct, both the license and professional services are determined to be a single performance obligation and the revenue is recognized over time based upon the Company's efforts to satisfy the performance obligation. Professional services revenue Professional services revenue primarily consists of fees for deployment and configuration services, as well as training services. Professional services revenues are generally recognized as the services are rendered for time and material contracts, or on a proportional performance basis for fixed fee contracts. The majority of the Company's professional services contracts are on a fixed fee basis. Training revenues are recognized as the services are rendered. Significant judgment is required in determining whether professional services contained in a customer subscription services contract are capable of being distinct and are separately identifiable in the customer contract. Professional services determined to be distinct are accounted for as a separate performance obligation and revenue is recognized as the services are performed. If the professional services are not determined to be distinct, the professional services and the subscription services are accounted for as a single performance obligation and revenue is recognized over the contractual term of the subscription beginning on the date that subscription services are made available to the customer. Customer contracts with multiple performance obligations A portion of the Company's customer contracts contain multiple performance obligations. Significant judgment is required in determining whether multiple performance obligations contained in a single customer contract are capable of being distinct and are separately identifiable. An obligation determined to be distinct is accounted for as a separate performance obligation and revenue for that separate performance obligation is recognized when, or as, the Company satisfies the performance obligation. If obligations are not determined to be distinct, those obligations are accounted for as a single, combined performance obligation. The transaction price is allocated to each performance obligation on a relative standalone selling price basis.
Lessee, Leases [Policy Text Block]	Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use ("ROU") assets, current operating lease liabilities and noncurrent operating lease liabilities in the Company's unaudited condensed consolidated balance sheet. ROU assets represent the Company’s right to use an underlying asset over the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the lease commencement date based on the estimated present value of lease payments over the lease term. The Company includes any anticipated lease incentives in the determination of lease liability. The Company uses its estimated incremental borrowing rate, which is derived from information available at the lease commencement date, in determining the present value of lease payments. The Company gives consideration to its recent debt issuances as well as publicly available data for instruments with similar characteristics when determining its incremental borrowing rates. The Company’s lease terms will include options to extend the lease when it is reasonably certain that the Company will exercise that option. Leases with a term of 12 months or less are not recorded on the Company's unaudited condensed consolidated balance sheet. The Company’s lease agreements do not contain any residual value guarantees.
Internal-use software	Internal-use software Costs incurred to develop internal-use software during the development stage are capitalized, stated at cost, and amortized 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 June 30, 2019 and 2018 , the Company capitalized zero and $1.1 million , respectively, of internal-use software development costs related to cloud-based offerings, and for the six months ended June 30, 2019 and 2018 , the Company capitalized $0.9 million and $2.5 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 months ended June 30, 2019 and 2018 , the Company amortized $0.8 million and $0.2 million , respectively, and for the six months ended June 30, 2019 and 2018 , the Company amortized $1.3 million and $0.3 million , respectively, of 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 and cost of services 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 six months ended June 30, 2019 and 2018 .
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, (ii) performance-based awards in which the number of shares that vest are based upon achievement of certain internal performance metrics set by the Company, and (iii) 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 June 30, 2019 and December 31, 2018 , respectively, (in thousands): Award type June 30, 2019 December 31, 2018 Restricted stock units (time-based) 1,876 1,969 Restricted stock units (performance-based) 114 — Restricted stock units (market-based) — 215 Stock appreciation rights 282 287 Market stock units 267 419 Stock options, time-based RSUs and SARs vest ratably between one and 4 years . Performance-based RSUs vest on the third anniversary of the grant and the maximum number of shares issuable upon vesting is 200% of the initially granted shares based upon achievement of certain internal performance metrics set by the Company, as defined by each award's plan documents or individual award agreements. 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, SARs or MSUs during the three and six months ended June 30, 2019 or 2018 . The fair value of the time-based and performance-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.
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 giving effect to all dilutive potential common shares outstanding during the period using the treasury stock method and convertible notes using the if-converted method. Dilutive potential common shares consist of shares issuable upon the exercise of stock options, shares of unvested restricted stock units and market 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, restricted stock units, market stock units and convertible notes 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.
Cost Method Investments, Policy [Policy Text Block]	Equity 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 at cost, less impairment and adjusted for subsequent observable price changes obtained from orderly transactions for identical or similar investments issued by the same investee. Adjustments resulting from impairment, fair value, or observable price changes are accounted for in the unaudited condensed consolidated statements of comprehensive income (loss). As of June 30, 2019 and December 31, 2018 , the Company held $2.1 million and $2.0 million , respectively, of equity securities in a privately held company. This investment is accounted for at cost, less impairment and adjusted for subsequent observable price changes obtained from orderly transactions for identical or similar investments issued by the same investee. The Company estimates fair value of its equity 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 defined by Accounting Standard Codification ("ASC") 820, " Fair Value Measurement and Disclosure " ("ASC 820"). As of June 30, 2019 and December 31, 2018 , the Company determined there were no other-than-temporary impairments on its equity 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 $294.8 million and $268.6 million at June 30, 2019 and December 31, 2018 , 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 ASC 820.
Trade and Other Accounts Receivable, Unbilled Receivables, Policy [Policy Text Block]	Trade and other receivables Trade and other receivables are primarily comprised of trade receivables, net of allowance for doubtful accounts, contract assets and unbilled receivables. The Company records trade accounts receivable for its unconditional rights to consideration arising from the Company's performance under contracts with customers. The Company's standard billing terms are that payment is due upon receipt of invoice, payable generally within thirty to sixty days. The carrying value of such receivables, net of the allowance for doubtful accounts, represents their estimated net realizable value. The Company estimates its allowance for doubtful accounts for specific trade receivable balances based on historical collection trends, the age of outstanding trade receivables, existing economic conditions, and any financial security associated with the receivables. Contract assets represent conditional rights to consideration that have been recognized as revenue in advance of billing the customer. Unbilled receivables represent unconditional rights to consideration arising from contingent revenue that have been recognized as revenue in advance of billing the customer.
Revenue Recognition, Customer Acquisitions [Policy Text Block]	Deferred costs Sales commissions earned by the Company's sales representatives are considered incremental and recoverable costs of obtaining a customer contract. Sales commissions are deferred and amortized on a straight-line basis over the period of benefit, which the Company has determined to be five to eight years. The Company determined the period of benefit by taking into consideration its customer contracts, expected renewals of those customer contracts (as the Company currently does not pay an incremental sales commission), the Company's technology and other factors. The Company also defers amounts earned by employees other than sales representatives who earn incentive payments under compensation plans that are also tied to the value of customer contracts acquired. Deferred costs were $19.4 million and $17.5 million as of June 30, 2019 and December 31, 2018 , respectively. Amortization expense for the deferred costs was $1.1 million and $0.7 million for the three months ended June 30, 2019 and 2018 , respectively, and $2.2 million and $1.4 million for the six months ended June 30, 2019 and 2018 , respectively.
Deferred Charges, Policy [Policy Text Block]	Deferred implementation costs The Company capitalizes certain contract fulfillment costs, including personnel and other costs (such as hosting, employee salaries, benefits and payroll taxes), that are associated with arrangements where professional services are not distinct from other undelivered obligations in its customer contracts. The Company analyzes implementation costs and capitalizes those costs that are directly related to customer contracts, that are expected to be recoverable, and that enhance the resources which will be used to satisfy the undelivered performance obligations in those contracts. Deferred implementation costs are amortized ratably over the remaining contract term once the revenue recognition criteria for the respective performance obligation has been met and revenue recognition commences. Deferred implementation costs were $4.7 million and $3.9 million as of June 30, 2019 and December 31, 2018 , respectively. Amortization expense for the deferred implementation costs was $0.4 million and $0.1 million for the three months ended June 30, 2019 and 2018 , respectively, and $0.6 million and $0.2 million for the six months ended June 30, 2019 and 2018 , respectively. Deferred implementation costs are included in prepaid and other current assets and other assets, noncurrent in the unaudited condensed consolidated balance sheets. Amortization of deferred implementation costs is included in cost of subscription and cost of services revenues in the accompanying unaudited condensed consolidated statements of comprehensive income (loss).
Revenue Recognition, Deferred Revenue [Policy Text Block]	Deferred revenue Deferred revenue primarily consists of customer invoicing in advance of revenues being recognized. The Company generally invoices its customers annually in advance for subscription services and maintenance and support services. Deferred revenue that is anticipated to be recognized during the next twelve-month period is recorded as current deferred revenue and the remaining portion is recorded as long-term.
Credit Facility	Credit facility As of June 30, 2019 , the Company had no outstanding borrowings under its $50.0 million secured Credit Agreement ("Revolver") with the lenders party thereto and Wells Fargo Bank, National Association as agent for the lenders party thereto. The Company included $0.1 million of unamortized debt issuance costs related to the Revolver in prepaid and other current assets and other assets, noncurrent in the unaudited condensed consolidated balance sheets. For the three and six months ended June 30, 2019 and 2018 , the Company recorded an immaterial amount of amortization of debt issuance cost which is included in other income (expense), net in the unaudited condensed consolidated statements of comprehensive income (loss).
Income taxes	Income taxes The Company recorded an income tax provision of $0.2 million and tax benefit of $0.1 million for the three months ended June 30, 2019 and 2018 , respectively, and a tax provision of $0.5 million and zero for the six months ended June 30, 2019 and 2018 , respectively, primarily related to foreign income taxes and withholding taxes. The effective tax rate was (1.4)% and 0.8% for the three months ended June 30, 2019 and 2018 , respectively, and (1.3)% and 0.0% for the six months ended June 30, 2019 and 2018 , respectively. 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 and foreign and state taxes not based on income. 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 February 2016, the FASB issued ASU 2016-02, " Leases (Topic 842) " ("Topic 842"), which requires the lessee to recognize most leases on the balance sheet thereby resulting in the recognition of right-of-use ("ROU") assets and lease liabilities for those leases currently classified as operating leases. Lessor accounting remains largely unchanged from current guidance, however, Topic 842 provides improvements that are intended to align lessor accounting with the lessee model and with updated revenue recognition guidance. This standard took effect in the first quarter of 2019, including interim periods within that reporting period. The Company adopted Topic 842 as of January 1, 2019 using the modified retrospective method by recognizing the cumulative effect of initially applying the new standard as an adjustment to the opening balances of operating ROU assets and lease liabilities, while prior period amounts are not adjusted and continue to be reported in accordance with the Company's historic accounting under the prior lease accounting rules in ASC 840, " Leases ". The Company elected the package of practical expedients permitted under the transition guidance within the new Topic 842 standard for all asset classes, which among other things, allowed the Company to carryforward the historical lease classification. The Company also elected the hindsight practical expedient to determine the reasonably certain lease term for existing leases. The Company made an accounting policy election to not recognize leases with an initial term of 12 months or less on the balance sheet and instead would recognize those lease payments on a straight-line basis over the lease term in the unaudited condensed consolidated statement of comprehensive income (loss). The adoption of the standard had a material impact on the Company’s unaudited condensed consolidated balance sheet as a result of the increase of $26.9 million in assets and liabilities from recognition of ROU assets and lease liabilities. The standard did not have a material impact on the Company's unaudited condensed consolidated statement of comprehensive income (loss). In August 2018, the FASB issued ASU 2018-15, "Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract" ("Subtopic 350-40") . The amendment aligns the requirements for capitalizing implementation costs in a cloud computing arrangement service contract with the requirements for capitalizing implementation costs incurred to develop or obtain an internal-use software. The standard is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2019; early adoption is permitted. The Company early adopted Subtopic 350-40 prospectively effective January 1, 2019 and there was no impact on the Company's unaudited condensed consolidated financial statements as of the adoption date. In addition, the new standard had no significant impact on the unaudited condensed consolidated financial statements for the three and six months ended June 30, 2019 . Recently issued accounting pronouncements not yet adopted In January 2017, the FASB issued ASU 2017-04, " Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment " ("Topic 350"), 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 after January 1, 2017. The Company is currently assessing the impact of Topic 350 on its unaudited 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 six months ended June 30, 2019 , 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 Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2019
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 June 30, 2019 and December 31, 2018 , respectively, (in thousands): Award type June 30, 2019 December 31, 2018 Restricted stock units (time-based) 1,876 1,969 Restricted stock units (performance-based) 114 — Restricted stock units (market-based) — 215 Stock appreciation rights 282 287 Market stock units 267 419

Disaggregation of Revenue (Tabl

Disaggregation of Revenue (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue by Geography [Abstract]
Schedule of Disaggregation Of Revenue [Table Text Block]	The geographic information in the table below is presented for the three and six months ended June 30, 2019 and 2018 . The Company categorizes geographic revenues based on the location of the customer's headquarters. Because the Company's contracts are predominately denominated in U.S. dollars, it has limited exposure to foreign currency exchange risk as discussed under " Foreign Currency Exchange Risk " of Part I, Item 3 below. Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Revenue Percent Revenue Percent Revenue Percent Revenue Percent United States of America $ 20,862 33 % $ 16,566 35 % $ 40,642 34 % $ 33,928 35 % Europe 18,720 29 % 14,808 31 % 36,007 30 % 30,091 32 % The rest of the world 24,296 38 % 16,052 34 % 43,360 36 % 31,317 33 % Total revenue $ 63,878 100 % $ 47,426 100 % $ 120,009 100 % $ 95,336 100 %

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lease, Cost [Table Text Block]	The components of operating lease expense were as follows (in thousands): Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 Operating lease cost $ 2,244 $ 4,493 Variable lease cost 588 891 Sublease income (132 ) (149 ) Total lease cost $ 2,700 $ 5,235
Supplemental Lease Information [Table Text Block]	Supplemental information related to leases was as follows (in thousands): Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 Cash paid for amounts included in the measurement of lease liability: Operating cash flows from operating leases $ 1,866 $ 2,882
Supplemental Balance Sheet Information Related to Leases [Table Text Block]	June 30, 2019 Weighted average remaining lease term: Operating leases 8.1 years Weighted average discount rate: Operating leases 7.65 %
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	As of June 30, 2019 , maturities of lease liabilities were as follows (in thousands): Year Ending December 31, Amount Remaining 2019 $ 3,262 2020 5,184 2021 6,030 2022 4,588 2023 4,604 2024 and thereafter 38,716 Total operating lease payments 62,384 Less: Imputed interest (23,437 ) Less: Anticipated lease incentive (14,207 ) Total operating lease liabilities $ 24,740
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	As of December 31, 2018, the future minimum lease commitments related to lease agreements under Topic 840, the predecessor of Topic 842, were as follows: Year Ending December 31, Amount 2019 $ 4,164 2020 1,649 2021 5,115 2022 6,181 2023 5,679 2024 and thereafter 57,365 Total minimum lease payments $ 80,153

Earnings per Share (Table)

Earnings per Share (Table)	6 Months Ended
	Jun. 30, 2019
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 six months ended June 30, 2019 and 2018 : Three Months Ended June 30, Six Months Ended June 30, (in thousands, except per share data) 2019 2018 2019 2018 Numerator: Net loss $ (17,517 ) $ (16,844 ) $ (34,434 ) $ (35,700 ) Denominator: Weighted average shares (basic) 39,413 32,651 38,518 32,514 Dilutive effect of potential common shares — — — — Weighted average shares (diluted) 39,413 32,651 38,518 32,514 Basic loss per share $ (0.44 ) $ (0.52 ) $ (0.89 ) $ (1.10 ) Diluted loss per share $ (0.44 ) $ (0.52 ) $ (0.89 ) $ (1.10 )

Noncash Share-based Compensat_2

Noncash Share-based Compensation (Tables)	6 Months Ended
	Jun. 30, 2019
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 six months ended June 30, 2019 and 2018 : Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Share-based compensation: Cost of revenue $ 494 $ 398 $ 1,032 $ 880 Operating expenses: Selling and marketing 1,414 1,284 2,814 2,568 General and administrative 2,808 2,688 5,620 5,567 Research and development 1,263 1,092 2,559 2,383 Total included in operating expenses 5,485 5,064 10,993 10,518 Total share-based compensation expense $ 5,979 $ 5,462 $ 12,025 $ 11,398

Convertible debt (Tables)

Convertible debt (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Schedule of Debt [Table Text Block]	The following is a summary of the Company's convertible senior notes as of June 30, 2019 (in thousands): Date of Issuance Unpaid Principal Balance Net Carrying Amount Contractual Interest Rates Current Noncurrent 2% Convertible Senior Note due in 2019 ("2019 Notes") December 2014 $ 21,606 $ 21,121 — 2% 2% Convertible Senior Notes due in 2047 ("2047 Notes") June 2017 $ 106,250 — $ 91,061 2% 1% Convertible Notes due in 2024 ("2024 Notes") May 2019 $ 143,750 $ — $ 107,367 1%
Convertible Debt [Table Text Block]	The Notes consist of the following (in thousands): June 30, 2019 December 31, 2018 Liability component: Principal $ 271,606 $ 250,000 Less: debt discount and issuance cost, net of amortization (52,057 ) (24,810 ) Net carrying amount $ 219,549 $ 225,190 Equity component (1) $ 70,443 $ 37,560 (1) Recorded within additional paid-in capital in the consolidated balance sheet. As of June 30, 2019 , it included $28.7 million , $32.9 million and $8.8 million related to the 2019 Notes, the 2024 Notes and the 2047 Notes, respectively, which was net of $1.2 million , $1.1 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 June 30, Six Months Ended June 30, 2019 2018 2019 2018 Coupon interest $ 1,106 $ 1,250 $ 2,356 $ 2,500 Amortization of debt issuance costs 341 352 706 701 Amortization of debt discount 2,827 2,624 5,568 5,204 Total $ 4,274 $ 4,226 $ 8,630 $ 8,405

Summary of Significant Accoun_4

Summary of Significant Accounting Policies Significant Accounting Policies (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jan. 01, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies [Line Items]
Internal-use software development costs capitalized			$ 868,000	$ 2,484,000
Capitalized Computer Software, Amortization	$ 800,000	$ 200,000	1,300,000	300,000
Tangible Asset Impairment Charges			0
Treasury money market funds, at fair value	294,800,000		294,800,000			$ 268,600,000
Cost Method Investments, Fair Value Disclosure	2,100,000		2,100,000			2,000,000
Deferred Costs	19,400,000		19,400,000			17,500,000
Amortization of Deferred Charges	1,100,000	700,000	2,200,000	1,400,000
Capitalized Contract Cost, Net	4,700,000		4,700,000			3,900,000
Capitalized Contract Cost, Amortization	400,000	100,000	600,000	200,000
Line of Credit Facility, Amount Outstanding	0		0
Line of Credit Facility, Maximum Borrowing Capacity	50,000,000		50,000,000
Unamortized Debt Issuance Expense	100,000		100,000
Income Tax Expense (Benefit)	$ 236,000	$ (131,000)	$ 458,000	$ 1,000
Effective income tax rate	(1.40%)	0.80%	(1.30%)	0.00%
Operating Lease, Right-of-Use Asset	$ 23,215,000		$ 23,215,000			$ 0
Cloud-based product offerings [Member]
Summary of Significant Accounting Policies [Line Items]
Internal-use software development costs capitalized	$ 0	$ 1,100,000	$ 900,000	$ 2,500,000
Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			1 year
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period			1 year 3 days
Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			4 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period			1 year 11 months 23 days
Share-based Payment Arrangement, 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 Payment Arrangement, 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 Payment Arrangement, 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
Accounting Standards Update 2016-02 [Member]
Summary of Significant Accounting Policies [Line Items]
Operating Lease, Right-of-Use Asset					$ 26,900,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies Awards Outstanding (Details) - shares shares in Thousands	Jun. 30, 2019	Dec. 31, 2018
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	0	215
Stock appreciation rights
Awards outstanding [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	282	287
Market Share Units (MSUs) [Member]
Awards outstanding [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	267	419
Restricted Stock Unit - time based [Member]
Awards outstanding [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	1,876	1,969
Performance Shares [Member]
Awards outstanding [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	114	0

Deferred Revenue and Performa_2

Deferred Revenue and Performance Obligation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Deferred Revenue and Performance Obligation [Abstract]
Deferred Revenue, Revenue Recognized	$ 43.7	$ 33	$ 67.1	$ 51.7
Revenue, Remaining Performance Obligation, Amount	378		378
Revenue Remaining Performance Obligation, to be recognized within 12 months	$ 182.7		$ 182.7

Disaggregation of Revenue Reven

Disaggregation of Revenue Revenue by Geography (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues	$ 63,878	$ 47,426	$ 120,009	$ 95,336
Percentage of total revenue	100.00%	100.00%	100.00%	100.00%
UNITED STATES
Revenues	$ 20,862	$ 16,566	$ 40,642	$ 33,928
Percentage of total revenue	33.00%	35.00%	34.00%	35.00%
Europe [Member]
Revenues	$ 18,720	$ 14,808	$ 36,007	$ 30,091
Percentage of total revenue	29.00%	31.00%	30.00%	32.00%
The rest of the world [Member]
Revenues	$ 24,296	$ 16,052	$ 43,360	$ 31,317
Percentage of total revenue	38.00%	34.00%	36.00%	33.00%

Leases (Details)

Leases (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 2,244	$ 4,493
Variable Lease, Cost	588	891
Sublease Income	(132)	(149)
Lease, Cost	2,700	5,235
Operating Lease, Payments	$ 1,866	$ 2,882
Operating Lease, Weighted Average Remaining Lease Term	8 years 1 month 6 days	8 years 1 month 6 days
Operating Lease, Weighted Average Discount Rate, Percent	7.65%	7.65%
Unrecorded Unconditional Purchase Obligation	$ 1,500	$ 1,500
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year	1 year
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	5 years	5 years
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	14 years	14 years
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	14 years	14 years

Leases Schedule of lease liabil

Leases Schedule of lease liability maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remaining 2019	$ 3,262
2020	5,184
2021	6,030
2022	4,588
2023	4,604
2024 and thereafter	38,716
Operating Leases, Payments Due	62,384
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(23,437)
Lessee, Operating Lease, Anticipated Incentives	(14,207)
Operating Lease, Liability	$ 24,740
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity (ASC 840) [Abstract]
Operating Leases, Future Minimum Payments Due, Next Twelve Months		$ 4,164
Operating Leases, Future Minimum Payments, Due in Two Years		1,649
Operating Leases, Future Minimum Payments, Due in Three Years		5,115
Operating Leases, Future Minimum Payments, Due in Four Years		6,181
Operating Leases, Future Minimum Payments, Due in Five Years		5,679
Operating Leases, Future Minimum Payments, Due Thereafter		57,365
Operating Leases, Future Minimum Payments Due		$ 80,153

Earnings per Share (Details)

Earnings per Share (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Payment Arrangement [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive potential common shares excluded from computation of earnings per share	2	2.1	2	2.1
Convertible Debt Securities [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive potential common shares excluded from computation of earnings per share			4.8

Earnings per Share Basis and Di

Earnings per Share Basis and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator
Net income (loss)	$ (17,517)	$ (16,844)	$ (34,434)	$ (35,700)
Denominator
Weighted average shares (basic)	39,413,000	32,651,000	38,518,000	32,514,000
Dilutive effect of potential common shares	0	0	0	0
Weighted average shares (diluted)	39,413,000	32,651,000	38,518,000	32,514,000
Basic Earnings Per Share	$ (0.44)	$ (0.52)	$ (0.89)	$ (1.10)
Diluted earnings per share	$ (0.44)	$ (0.52)	$ (0.89)	$ (1.10)

Noncash Share-based Compensat_3

Noncash Share-based Compensation (Details)	3 Months Ended	6 Months Ended
	Jun. 30, 2019USD ($)$ / sharesshares	Jun. 30, 2019USD ($)$ / sharesshares
Noncash Share-based Compensation (Narrative) [Line Items]
Unrecognized compensation cost related to share-based compensation | $	$ 51,500,000	$ 51,500,000
Weighted average period to recognize cost, in years		2 years 8 months 12 days
Share-based compensation arrangement by share-based payment, Minimum Employee Subscription rate	1.00%	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	0	35,340
ESPP contributions by Employees | $		$ 1,100,000
RSUs
Noncash Share-based Compensation (Narrative) [Line Items]
Awards, other than options, granted in period	3,643	739,459
Weighted average grant date fair value, per share, of awards granted in period | $ / shares	$ 52.15	$ 33.23
MSUs
Noncash Share-based Compensation (Narrative) [Line Items]
Awards, other than options, granted in period		113,919
Weighted average grant date fair value, per share, of awards granted in period | $ / shares		$ 33.05
Employee Stock [Member]
Noncash Share-based Compensation (Narrative) [Line Items]
Shares available for future grants	180,215	180,215
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	2,523,987	2,523,987
2017 Amended Equity Incentive Plan [Member]
Noncash Share-based Compensation (Narrative) [Line Items]
Shares reserved for issuance under Plan	4,550,000	4,550,000
Share-based Payment Arrangement, 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 Payment Arrangement, 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 Payment Arrangement, 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 Compensat_4

Noncash Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 5,979	$ 5,462	$ 12,025	$ 11,398
Cost of Sales [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	494	398	1,032	880
Selling and Marketing Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	1,414	1,284	2,814	2,568
General and Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	2,808	2,688	5,620	5,567
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	1,263	1,092	2,559	2,383
Operating Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 5,485	$ 5,064	$ 10,993	$ 10,518

Convertible debt (Details)

Convertible debt (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)$ / shares	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)$ / sharesshares	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Payment for Debt Extinguishment or Debt Prepayment Cost			$ (75,958)	$ 0
Stock Issued During Period, Shares, Conversion of Convertible Securities | shares			2,180
Gain (Loss) on Extinguishment of Debt			$ (2,266)	0
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	2.00%		2.00%
Partial Extinguishment of Debt, Principal Amount			$ 122,100
Debt Instrument, Face Amount	$ 271,606		271,606		$ 250,000
Convertible Debt, Current	21,121		21,121		136,529
Convertible Debt, Noncurrent	198,428		198,428		88,661
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	52,057		52,057		24,810
Convertible Debt	219,549		219,549		225,190
Debt Instrument, Convertible, Carrying Amount of Equity Component	70,443		70,443		37,560
Debt Instrument, Periodic Payment, Interest	1,106	$ 1,250	2,356	2,500
Amortization of Financing Costs	341	352	706	701
Amortization of Debt Discount (Premium)	2,827	2,624	5,568	5,204
Interest Expense, Debt	4,274	$ 4,226	8,630	8,405
Debt Instrument, Fair Value Disclosure	350,500		350,500		$ 251,500
Purchase of convertible bond hedge			(16,445)	0
Proceeds from bond hedge termination			64,819	0
Payment for warrant termination			(45,243)	$ 0
Notes due 2047 [Member]
Debt Instrument [Line Items]
Debt Issuance Cost	2,700		2,700
Convertible debt, issuance cost, equity component			300
Debt Instrument, Face Amount	106,250		106,250
Convertible Debt, Current	0		0
Convertible Debt, Noncurrent	91,061		91,061
Debt Instrument, Convertible, Carrying Amount of Equity Component	8,800		$ 8,800
Debt Instrument, Convertible, Remaining Discount Amortization Period			35 months
Notes due 2019 [Member]
Debt Instrument [Line Items]
Debt Issuance Cost	4,300		$ 4,300
Convertible debt, issuance cost, equity component			$ 1,200
Debt Instrument, Convertible, Stock Price Trigger | $ / shares			$ 33.79
Debt Instrument, Face Amount	21,606		$ 21,606
Convertible Debt, Current	21,121		21,121
Convertible Debt, Noncurrent	0		0
Debt Instrument, Convertible, Carrying Amount of Equity Component	28,700		$ 28,700
Debt Instrument, Convertible, Remaining Discount Amortization Period			5 months
Purchase of convertible bond hedge			$ 29,400
Investment Warrants, Exercise Price | $ / shares			$ 45.48
Proceeds from Issuance of Warrants			$ 17,100
Notes due 2024 [Member]
Debt Instrument [Line Items]
Debt Issuance Cost	$ 3,400		3,400
Convertible debt, issuance cost, equity component			$ 1,100
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	1.00%		1.00%
Debt Instrument, Convertible, Conversion Ratio			15.1394
Debt Instrument, Convertible, Stock Price Trigger | $ / shares			$ 66.05
Debt Instrument, Convertible, Conversion Price | $ / shares	$ 101.62		$ 101.62
Debt Instrument, Face Amount	$ 143,750		$ 143,750
Convertible Debt, Current	0		0
Convertible Debt, Noncurrent	107,367		107,367
Debt Instrument, Convertible, Carrying Amount of Equity Component	$ 32,900		$ 32,900
Debt Instrument, Convertible, Remaining Discount Amortization Period			58 months

Commitments and Contingencies P

Commitments and Contingencies Purchase commitments (Details) $ in Millions	Jun. 30, 2019USD ($)
Long-term Purchase Commitment [Line Items]
Purchase Obligation	$ 68.5