CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets
Accounts receivable allowance	$ 1,729	$ 2,181
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	160,000,000	160,000,000
Common stock, shares issued	50,177,044	48,748,298
Common stock, shares outstanding	50,166,537	48,303,811