Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Mar. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0025	$ 0.0025
Preferred stock, shares authorized	10,000	10,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0025	$ 0.0025
Common stock, shares authorized	100,000	100,000
Common stock, shares issued	42,664	42,526
Common stock, shares outstanding	42,664	42,526