CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Activities:
Net loss	$ (42,974)	$ (42,203)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,311	715
Amortization of discount on marketable securities	(744)	(1,238)
Amortization and other changes in right-of-use assets	1,886	782
Loss (gain) on free shares	73	(545)
Stock-based compensation	5,620	4,523
Net loss on lease termination	0	218
Other	0	44
Net changes in operating assets and liabilities:
Interest receivable	(244)	(219)
Accounts receivable	29,939	(2,638)
Prepaid expenses and other assets	(100)	1,152
Prepaid rent	0	(12,101)
Accounts payable and accrued liabilities	345	10,183
Accrued compensation and employee benefits	(4,965)	(3,306)
Deferred revenues	(8,319)	(370)
Long-term portion of lease liabilities	(887)	(66)
Other non-current liabilities	169	(50)
Net cash used in operating activities	(18,890)	(45,119)
Investing Activities:
Purchases of marketable securities	(43,580)	(87,075)
Maturities of marketable securities	71,075	78,253
Purchases of property and equipment	(3,775)	(5,977)
Net cash provided by (used in) investing activities	23,720	(14,799)
Financing Activities:
Taxes paid related to net share settlement of equity awards	(411)	(265)
Proceeds from exercise of stock options and restricted stock units	820	481
Net cash provided by financing activities	409	216
Effects of changes in foreign exchange rates	82	252
Net increase (decrease) in cash, cash equivalents, and restricted cash	5,321	(59,450)
Cash, cash equivalents, and restricted cash, beginning of period	81,928	143,918
Cash, cash equivalents, and restricted cash, end of period	87,249	84,468
Supplemental disclosure of non-cash activities:
Property and equipment included in unpaid liabilities	1,080	1,834
Right-of-use assets obtained in exchange for lease obligations	$ 0	$ 6,676