CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,338	$ 833
Preferred stock, par value	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	98,208,117	89,935,381
Common stock, shares outstanding	88,560,409	81,995,286