Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (92,983)	$ (90,270)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	12,473	14,897
(Accretion) amortization of (discount) premium on investment debt securities	536	(299)
Amortization of deferred financing costs	614	406
Depreciation	764	996
Non-cash operating lease cost	1,584	1,404
Gain on lease termination		(1,995)
Loss on the disposal of fixed assets		2,683
Accretion of debt discount	6,276	3,695
Provision for allowance of credit losses	179
Changes in operating assets:
Accounts receivable	(6,549)	(3,746)
Prepaid expenses and other current assets	(7,122)	752
Inventory	(2,377)	(262)
Security deposits	50	883
Other assets		(19,716)
Changes in operating liabilities:
Accounts payable, accrued expenses and other current liabilities	(7,899)	(800)
Operating lease liabilities	(1,690)	(1,638)
Interest payable	(2,587)	(3,737)
Deferred revenue		690
Long-term other liabilities		12,632
Net cash (used in) operating activities	(98,731)	(83,425)
Cash flows from investing activities:
Purchases of investment debt securities	(34,444)	(5,212)
Sales and maturities of investment debt securities	106,693	100,412
Purchases of equipment, leasehold improvements, and furniture and fixtures	(432)	(733)
Net cash provided by investing activities	71,817	94,467
Cash flows from financing activities:
Proceeds from exercise of options, net	569	943
Payments of employee withholding taxes related to stock-based awards	(1,322)	(791)
Net cash (used in) provided by financing activities	(753)	152
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(694)	282
Net (decrease) increase in cash, cash equivalents and restricted cash	(28,361)	11,476
Cash, cash equivalents and restricted cash at beginning of period	74,780	43,248
Cash, cash equivalents and restricted cash at end of period	$ 46,419	$ 54,724