Commitments and Contingencies - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
	Nov. 10, 2009	Dec. 31, 2013 Lease Lawsuits sqft	Dec. 31, 2012	Dec. 31, 2011
Commitments and Contingencies [Line Items]
Operating lease		38,536
Stand by letter of credit		$ 571,000
Restricted cash		571,000
Lease additional extended term		2
Number of years lease can be extended		5 years
Rent expense		2,200,000	2,200,000	2,200,000
Annual maintenance payments recorded as research and development expense		54,502,000	41,037,000	31,253,000
License agreements amount		72,000	30,000	30,000
Milestone payment period		5 years
Contract term		5 years
Milestone payment		0
Accumulated discounted labor cost		220,000
Number of days for election		30 days
Milestones payment		100,000
Total expense incurred under milestone payment agreements		400,000	0	400,000
Milestone payment on occurrence of regulatory event required		300,000
Milestone payment accrual on occurrence of regulatory event		0
Period under contract term to declare development candidate for milestone Payments forgo		3 years
Milestone possible earning period	10 years
Legal proceedings		0
Minimum [Member]
Commitments and Contingencies [Line Items]
Range related to royalties amount		0.50%
Range related to non royalties amount		7.00%
Maximum [Member]
Commitments and Contingencies [Line Items]
Range related to royalties amount		2.50%
Range related to non royalties amount		25.00%
Preclinical Milestones [Member]
Commitments and Contingencies [Line Items]
Milestones payment		200,000
Regulatory Milestones [Member]
Commitments and Contingencies [Line Items]
Milestones payment		200,000
Milestone One [Member]
Commitments and Contingencies [Line Items]
Upfront grant money to be utilized in development and testing brain cancer therapy	178,538
Accumulated net profit	5,000,000
Milestone Two [Member]
Commitments and Contingencies [Line Items]
Upfront grant money to be utilized in development and testing brain cancer therapy	178,538
Accumulated net profit	50,000,000
Milestone Three [Member]
Commitments and Contingencies [Line Items]
Upfront grant money to be utilized in development and testing brain cancer therapy	178,538
Accumulated net profit	250,000,000
Office and Laboratory Space [Member]
Commitments and Contingencies [Line Items]
Date of expiry of lease		Apr. 14, 2016
License Agreement Terms [Member]
Commitments and Contingencies [Line Items]
Milestone payments		100,000
Payments made in consideration for the licensed rights		470,000
Shares of common stock issued to certain licensors		162,545
Annual maintenance payments recorded as research and development expense		35,000
Payment of patent related to licensor		200,000
Payment of clinical development related to licensor		1,600,000
Regulatory payment related to licensor		5,400,000
Sales based payment related to licensor		3,700,000
Patent-based payment related to licensor		25,000	0	0
Royalties paid		$ 0
Option to renew licenses		Option to renew these licenses on an annual basis in exchange for payments approximating $45,000 for 2014