Correction of Immaterial Errors Within Previously Issued Consolidated Financial Statements - Condensed Consolidated Statement of Cash Flows (Detail) (USD $)	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
As Reported [Member]
Net income (loss)	$ (12,966,000)	$ 64,612,000
Changes in operating expenses and liabilities:
Depreciation and amortization	6,618,000	4,043,000
Accounts payable and other accrued obligations	(9,671,000)	36,409,000
Accrued drug development costs	(2,213,000)	932,000
Net cash provided by operating activities	3,444,000	44,949,000
As Restated [Member]
Net income (loss)	(15,157,000)	65,187,000
Changes in operating expenses and liabilities:
Depreciation and amortization	10,772,000	4,043,000
Accounts payable and other accrued obligations	(11,495,000)	36,489,000
Accrued drug development costs	(2,352,000)	277,000
Net cash provided by operating activities	$ 3,444,000	$ 44,949,000