Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 4,479	$ 4,180
Property and equipment, accumulated depreciation	$ 24,791	$ 19,822
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	60,598,616	60,242,818
Common stock, shares outstanding	60,598,616	60,242,818