CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net loss	$ (73,859)	$ (154,740)	$ (24,010)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	44,832	47,166	42,391
Non-cash leases expense	12,537	0	0
Stock-based compensation expense, net of amounts capitalized	60,245	131,770	34,986
Amortization of debt discount and issuance costs	301	902	876
Deferred income taxes	(3,676)	(508)	(16,848)
Loss on debt extinguishment	0	941	194
Gain on sale of a private company investment	(1,001)	(999)	(6,750)
Impairment of property and equipment	0	2,821	0
Other	(157)	1,798	(829)
Changes in assets and liabilities:
Accounts receivable	(7,239)	(1,958)	675
Prepaid expenses and other assets	(5,172)	(5,565)	867
Accounts payable and accrued liabilities	8,318	3,564	(2,061)
Accrued interest on financing lease obligation, net of payments	0	(1,376)	4,580
Accrued compensation	2,232	5,203	2,327
Deferred revenue	31,181	16,353	8,628
Operating lease liabilities	(13,890)	0	0
Net cash provided by operating activities	54,652	45,372	45,026
Cash flows from investing activities
Acquisitions, net of cash acquired	(114,603)	0	0
Purchases of property and equipment	(2,450)	(9,981)	(32,488)
Capitalized internal-use software	(12,034)	(12,052)	(15,319)
Proceeds from sale of a private company investment	1,001	999	15,453
Net cash used in investing activities	(128,086)	(21,034)	(32,354)
Cash flows from financing activities
Proceeds from initial public offering, net	0	232,509	0
Payments of deferred offering costs	0	(7,173)	0
Proceeds from stock option exercises	47,678	494	153
Proceeds from employee stock purchase plan	5,344	0	0
Employee payroll taxes paid for net share settlement of restricted stock units	0	(25,807)	(6,934)
Payments to repurchase common stock	0	(16)	(144)
Proceeds from term and revolving debt issuance	0	0	298,500
Repayment of debt	(2,200)	(104,050)	(298,883)
Payment of debt issuance costs and other	0	(482)	(1,666)
Proceeds from tenant improvement allowances under lease financing obligation	0	0	8,360
Net cash provided by (used in) financing activities	50,822	95,475	(614)
Effect of exchange rate changes on cash	(76)	(787)	0
Net increase (decrease) in cash, cash equivalents and restricted cash	(22,688)	119,026	12,058
Cash, cash equivalents and restricted cash at beginning of period	154,371	35,345	23,287
Cash, cash equivalents and restricted cash at end of period	131,683	154,371	35,345
Supplemental cash flow data:
Interest paid for term debt	13,502	20,466	19,864
Interest paid for financing obligation on leased facility	0	8,152	2,038
Cash paid for operating leases	13,777	0	0
Income taxes paid	756	535	547
Non-cash investing and financing transactions:
Fair value of common stock issued as acquisition consideration	36,204	0	0
Stock compensation included in capitalized software costs	3,503	2,609	3,119
Accrued unpaid capital expenditures	171	322	1,214
Lease liabilities arising from obtaining right-of-use assets	7,937	0	0
Derecognized financing obligation related to building due to adoption of ASC 842	92,009	0	0
Derecognized building due to adoption of ASC 842	$ 71,781	$ 0	$ 0