Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest
Balance at beginning of year (in shares) at Dec. 31, 2018		66,618
Balance at beginning of year at Dec. 31, 2018	$ 90,567	$ 68	$ 1,614,320	$ (1,525,704)	$ (283)	$ 2,166
Issuance of common stock pursuant to equity award plans (in shares)		1,359
Issuance of common stock pursuant to equity award plans	25,662	$ 2	25,660
Stock-based compensation expense	12,312		12,312
Other comprehensive income	203				203
Net (loss) income	(78,096)			(78,156)		60
Change in noncontrolling interest	2					2
Balance at end of the year (in shares) at Mar. 31, 2019		67,977
Balance at end of the year at Mar. 31, 2019	50,650	$ 70	1,652,292	(1,603,860)	(80)	$ 2,228
Balance at beginning of year (in shares) at Dec. 31, 2019		77,925
Balance at beginning of year at Dec. 31, 2019	129,825	$ 80	1,946,077	(1,816,367)	35
Issuance of common stock pursuant to equity award plans (in shares)		559
Issuance of common stock pursuant to equity award plans	379		379
Stock-based compensation expense	9,807		9,807
Other comprehensive income	793				793
Net (loss) income	(68,771)			(68,771)
Balance at end of the year (in shares) at Mar. 31, 2020		78,484
Balance at end of the year at Mar. 31, 2020	$ 72,033	$ 80	$ 1,956,263	$ (1,885,138)	$ 828