Stockholders' Equity - Additional Information 1 (Detail) - Stockholder Rights Plan [Member]		12 Months Ended
	Jul. 10, 2006 Right $ / shares $ / Right shares	Dec. 31, 2016
Stockholders Equity [Line Items]
No of right for each share | Right	1
Description of event for occurrence of right		Acquisition of, 15% or more of our common stock
Portion of newly created Series A Preferred Stock for each Right | shares	0.001
Series A Junior Participating Preferred Stock , Exercise Price | $ / shares	$ 40.00
Expiration of plan		Jul. 10, 2016
Series A Preferred Stock [Member]
Stockholders Equity [Line Items]
Redemption of right | $ / Right	0.001