Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Consolidated Balance Sheets
Accounts receivable, allowance for doubtful accounts	$ 4,508	$ 3,988
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	34,893,329	33,861,759
Common stock, shares outstanding	33,831,998	32,800,428
Treasury stock, shares	1,061,331	1,061,331