Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,121	$ 936
Common stock, par value, per share	$ 0.0001	$ 0.0001
Common stock, shares authorized	145,000,000	145,000,000
Common stock, shares issued	34,733,955	34,233,888
Common stock, shares outstanding	34,733,955	34,233,888