CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred stock par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock authorized (in shares)	33,333	33,333
Preferred stock issued (in shares)	12,575	12,575
Preferred stock outstanding (in shares)	12,575	12,575
Preferred stock liquidation preference	$ 25,150	$ 25,150
Common stock par value (in dollars per share)	$ 0.001	$ 0.001
Common stock authorized (in shares)	101,500,000	101,500,000
Common stock issued (in shares)	57,979,325	57,986,075
Common stock outstanding (in shares)	57,979,325	57,986,075