CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Allowance for doubtful accounts	$ 1,502	$ 1,242
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	51,001,395	50,698,587
Common stock, shares outstanding (in shares)	50,340,014	50,037,206
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	1	1
Preferred stock, shares outstanding (in shares)	1	1
Treasury stock (in shares)	661,381	661,381
Treasury Stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001