Business and Basis of Presentation - Basic and Diluted Net Income (Loss) Per Share Using Weighted Average Number of Common Shares Outstanding (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive preferred shares	40,000		40,000
Dilutive options	2,412,230		3,211,911
Incremental shares assumed issued on exercise of in the money warrants	115,249		173,031
Unvested restricted stock	1,102,654		1,102,654
Antidilutive options excluded from the calculation, Weighted-Average Shares Outstanding (Denominator)	3,670,133		4,527,596
As Restated [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted-Average Shares Outstanding (Denominator), Basic	58,977,295	58,763,700	58,995,735	58,617,530
Net income (loss)	$ (9,721,000)	$ 18,350,000	$ (15,157,000)	$ 65,187,000
Dilutive preferred shares		40,000		40,000
Dilutive options		4,069,118		4,483,596
Incremental shares assumed issued on exercise of in the money warrants		251,578		269,403
Unvested restricted stock		262,607		256,017
Weighted-Average Shares Outstanding (Denominator), Diluted	58,977,295	63,387,003	58,995,735	63,666,546
Earnings (Loss) Per Share, Basic and diluted	$ (0.16)	$ 0.31	$ (0.26)	$ 1.11
Earnings Per Share, Diluted	$ (0.16)	$ 0.29	$ (0.26)	$ 1.02
As Restated [Member] | Antidilutive options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive options excluded from the calculation, Weighted-Average Shares Outstanding (Denominator)		301,708		155,750