Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Allowance on accounts receivable	$ 2,094	$ 1,840
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	20,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	60,000,000
Common stock, shares issued	40,854,491	39,696,110
Common stock, shares outstanding	40,854,491	39,696,110