CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets
Accounts receivable allowance	$ 1,419	$ 1,434
Prepaid and other assets allowance	292	644
Employee loans current allowance	0	0
Assets, Noncurrent [Abstract]
Employee loans long-term allowance	0	0
Other long-term assets allowance	$ 138	$ 132
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 )	52,476,671	51,117,422
Common stock, shares outstanding (in shares)	52,456,936	51,097,687