CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities
Net loss	$ (36,255)	$ (27,180)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	20,545	23,652
Non-cash leases expense	6,059	0
Stock-based compensation expense, net of amounts capitalized	30,265	17,292
Amortization of debt discount and issuance costs	150	484
Deferred income taxes	(415)	295
Gain on sale of a private company investment	(1,001)	(999)
Other	51	176
Changes in assets and liabilities:
Accounts receivable	(1,830)	(814)
Prepaid expenses and other assets	(3,387)	(3,753)
Accounts payable and accrued liabilities	1,996	2,624
Accrued interest on financing lease obligation, net of payments	0	(703)
Accrued compensation	(6,311)	(3,554)
Deferred revenue	18,576	14,511
Operating lease liabilities	(6,731)	0
Net cash provided by operating activities	21,712	22,031
Cash flows from investing activities
Acquisition, net of cash acquired	(53,138)	0
Purchases of property and equipment	(1,335)	(4,809)
Capitalized internal-use software	(6,527)	(5,467)
Proceeds from sale of a private company investment	1,001	999
Net cash used in investing activities	(59,999)	(9,277)
Cash flows from financing activities
Proceeds from stock option exercises	37,593	178
Proceeds from employee stock purchase plan	2,662	0
Employee payroll taxes paid for net share settlement of restricted stock units	0	(3,218)
Repayment of debt	(1,100)	(1,500)
Net cash provided by (used in) financing activities	39,155	(4,540)
Effect of exchange rate changes on cash	(55)	0
Net increase in cash, cash equivalents and restricted cash	813	8,214
Cash, cash equivalents and restricted cash at beginning of period	154,371	35,345
Cash, cash equivalents and restricted cash at end of period	155,184	43,559
Supplemental cash flow data:
Interest paid for term debt	6,913	10,813
Interest paid for financing obligation on leased facility	0	4,076
Cash paid for operating leases	6,731	0
Income taxes paid	676	50
Non-cash investing and financing transactions:
Fair value of common stock issued as acquisition consideration	30,092	0
Stock compensation included in capitalized software costs	2,031	756
Accrued unpaid capital expenditures	321	2,098
Lease liabilities arising from obtaining right-of-use assets	2,477	0
Derecognized financing obligation related to building due to adoption of ASC 842	92,009	0
Derecognized building due to adoption of ASC 842	$ 71,781	$ 0