Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2018	$ 479,079	$ 14	$ 1,948,300	$ (1,468,863)	$ (372)
Issuance of common stock from exercise of stock options			4,176
Stock-based compensation			19,826
Net loss	(85,304)			(85,304)
Ending balance at Mar. 31, 2019	418,356	14	1,972,302	(1,554,167)	207
Other comprehensive (loss) income	579
Beginning balance at Dec. 31, 2019	699,135	15	2,402,945	(1,704,122)	297
Issuance of common stock from exercise of stock options			3,754
Stock-based compensation			22,288
Net loss	(88,023)			(88,023)
Ending balance at Mar. 31, 2020	638,382	$ 15	$ 2,428,987	$ (1,792,145)	$ 1,525
Other comprehensive (loss) income	$ 1,228