CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets
Accounts receivable allowance	$ 2,301	$ 1,729
Employee loans current allowance	0	0
Noncurrent assets
Employee loans long-term allowance	$ 0	$ 0
Stockholders' equity
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	160,000,000	160,000,000
Common stock, shares issued (in shares )	51,035,509	50,177,044
Common stock, shares outstanding (in shares)	51,016,500	50,166,537