Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 5,377	$ 3,114
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	90,000,000	90,000,000
Common stock, shares issued (in shares)	28,996,039	27,206,162
Common stock, shares outstanding (in shares)	28,996,039	27,206,162