Stock-Based Compensation - Summary of Outstanding Restricted Stock Awards and Related Activity (Detail) - Restricted stock [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, beginning balance	1,725	1,746	1,319
Number of shares, Granted	1,375	1,625	1,495
Number of shares, Vested	(1,011)	(1,442)	(752)
Number of shares, Cancelled and forfeited	(284)	(204)	(316)
Number of shares, ending balance	1,805	1,725	1,746
Weighted average grant date fair value, beginning balance	$ 1.91	$ 2.48	$ 4.60
Weighted average grant date fair value, Granted	1.50	1.79	1.70
Weighted average grant date fair value, Vested	1.95	2.48	4.43
Weighted average grant date fair value, Cancelled and forfeited	1.67	1.79	3.00
Weighted average grant date fair value, ending balance	$ 1.61	$ 1.91	$ 2.48