Licenses Acquired - Additional Information (Detail)

v3.19.1

Licenses Acquired - Additional Information (Detail) - USD ($)					1 Months Ended																							12 Months Ended
	Feb. 11, 2019	Jul. 03, 2018	Jul. 03, 2017	May 11, 2015	Oct. 29, 2018	Sep. 30, 2018	Mar. 31, 2018	Jan. 31, 2018	Nov. 30, 2017	Nov. 30, 2017	Nov. 20, 2017	Oct. 31, 2017	May 31, 2017	Apr. 25, 2017	Mar. 31, 2017	Mar. 17, 2017	Jan. 31, 2017	Oct. 31, 2016	Sep. 30, 2016	May 31, 2016	Mar. 31, 2016	Oct. 30, 2015	Sep. 30, 2015	Jun. 17, 2015	Apr. 28, 2015	Mar. 31, 2015	Feb. 28, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 26, 2017
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments to Acquire Intangible Assets																												$ 1,200,000	$ 0
Research and Development in Process																												$ 4,050,000	4,164,000
Shares Issued, Price Per Share																												$ 2.50				$ 6.00
Payments for Fees									$ 2,700,000	$ 100,000
Stock Issued During Period, Shares, Issued for Services																							136,830
Stock Issued During Period, Value, Issued for Services																							$ 600,000					$ 500,000
Research and Development Expense																												83,333,000	48,322,000
Share Price		$ 3.04
Payment of Upfront Fees																												1,000,000
Revenue Recognition Milestone Method Payments Due					$ 2,000,000
Proceeds from Issuance of Common Stock	$ 13,100,000																											$ 10,000,000
Stock Issued During Period, Shares, New Issues		164,473					5,290,000					43,292																1,841,774
Additional Annual License fee																												$ 75,000
Revenue from Contract with Customer, Including Assessed Tax																												23,376,000	15,520,000
Cost, Maintenance																												$ 25,000	50,000
IV Tramadol [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments for Fees																											$ 200,000
Development Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																											10,700,000
Sale Millstone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																											26,200,000
NeuPharma [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																										$ 1,000,000				$ 1,000,000
NeuPharma [Member] | Development Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																										40,000,000
NeuPharma [Member] | Sale Millstone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																										40,000,000
NeuPharma [Member] | Regulatory Approvals To Commercialize Products [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																										$ 22,500,000
City Of Hope [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Marketability Percentage Of Invested Capital																										44.80%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage																										30.00%
Share Price																										$ 0.147
Stock Issued During Period, Value, Other																										$ 100,000
Payment of Upfront Fees															$ 100,000										$ 2,000,000
Revenue Recognition Milestone Method Payments Due															$ 100,000
UCLA License [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																$ 14,300,000
Tamid [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																													$ 300,000
Share Price																													$ 0.015
Stock Issued During Period, Shares, New Issues																													1,000,000
Equity Method Investment, Ownership Percentage																													10.00%
Proceeds from License Fees Received																													$ 15,000
Fair Values Assumptions Expected Volatility Rate																													75.00%
Fair Values Inputs Discount For Lack Of Marketability																													40.50%
Dana Farber Cancer Institute [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Shares Issued, Price Per Share				$ 0.065
Stock Issued During Period, Shares, Issued for Services				500,000
Stock Issued During Period, Value, Issued for Services				$ 32,500
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners																												5.00%
Dana Farber Cancer Institute [Member] | First Commercial Sale Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																							21,500,000
Dana Farber Cancer Institute [Member] | Additional Sales Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																							$ 60,000,000
Mustang Bio, Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Royalty Guarantees, Commitments, Amount																										$ 1,000,000
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners																										10.00%
Annual Maintenance Fee Payable																										$ 1,000,000
Mustang Bio, Inc [Member] | Development Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																										14,500,000
Mustang Bio, Inc [Member] | Financial Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due														$ 200,000												2,000,000
Effcon Laboratories, Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payment of Upfront Fees																			$ 200,000
Revenue Recognition Milestone Method Payments Due																			5,300,000
Royalty Guarantees, Commitments, Amount																			$ 1,600,000
Teva Pharmaceutical Industries Ltd [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments for Fees																															$ 500,000
Jubilant Biosys Ltd [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																												$ 87,200,000
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners																												50.00%
Payment Of Upfront Licensing Fee																				$ 2,000,000
Payments of Milestone																													$ 400,000
Jubilant Biosys Ltd [Member] | Sale Millstone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone Method Revenue Additional Payments Eligible To Receive																				89,000,000
Jubilant Biosys Ltd [Member] | Regulatory Approvals To Commercialize Products [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																				59,500,000
Jubilant Biosys Ltd [Member] | Completion Of Three Clinical Development Milestones For Two Licensed Products [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																												$ 25,500,000
Jubilant Biosys Ltd [Member] | Five Regulatory Approvals And First Commercial Sales [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																												61,700,000
Jubilant Biosys Ltd [Member] | Three Sales Milestones Based On Aggregate Net Sales [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																												89,000,000
Jubilant Biosys Ltd [Member] | Clinical Development and Regulatory Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																				$ 89,000,000
Columbia University [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Stock Issued During Period, Shares, Purchase of Assets																	1,050,000
Shares Issued, Price Per Share																	$ 0.028
Stock Issued During Period, Value, Purchase of Assets																	$ 29,000
Payment of Upfront Fees																	200,000
Revenue Recognition Milestone Method Payments Due																	$ 5,500,000
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners																	10.00%
Fair Values Assumptions Expected Volatility Rate																	70.00%
Fair Values Assumptions Expected Term																	5 years
Fair Values Assumptions Risk Free Interest Rate																	1.93%
Fair Values Inputs Discount For Lack Of Marketability																	49.50%
Collaborative Agreements with TGTX [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments for Fees																												500,000
Collaborative Agreements with TGTX [Member] | NeuPharma [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments for Fees																												3,000,000	100,000
Agreement With City Of Hope [Member] | Mustang Bio, Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payment of Upfront Fees											$ 300,000
Triplex [Member] | City Of Hope [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Minimum Annual Royalty Payable																									750,000
Pentameter [Member] | City Of Hope [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Minimum Annual Royalty Payable																									750,000
Pentameter [Member] | City Of Hope [Member] | Development Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																									5,500,000
Pentameter [Member] | City Of Hope [Member] | Sale Millstone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																									26,000,000
Royalty [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue from Contract with Customer, Including Assessed Tax																												400,000	1,000,000
Coronado SO Co, Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process												$ 50,000
Payments for Fees																											$ 900,000
Stock Issued During Period, Shares, Other																											150,000
Research and Development Expense																						$ 500,000
Payment For Research And Development Licenses												$ 200,000
Proceed from sale of milestone payment																												1,800,000
Stock Issued During Period, Shares, New Issues												4.6197
Checkpoint Therapeutics, Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																												1,000,000	400,000
Stock Issued During Period, Value, Purchase of Assets																												22,000,000
Checkpoint Therapeutics, Inc [Member] | First Commercial Sale Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																												21,500,000
Checkpoint Therapeutics, Inc [Member] | Additional Sales Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																												60,000,000
Checkpoint Therapeutics, Inc [Member] | Clinical Development Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																												7,000,000
Checkpoint Therapeutics, Inc [Member] | Commercial Sales In Specified Territories [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																												14,500,000
Checkpoint Therapeutics, Inc [Member] | Dana Farber Cancer Institute [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Stock Issued During Period, Value, Purchase of Assets																												4,100,000	4,200,000
Helocyte [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																												1,521,000	0
Payments For Research And Development Expenses																												1,500,000	0
Helocyte [Member] | Triplex [Member] | Development Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																									26,000,000
Helocyte [Member] | Triplex [Member] | Sale Millstone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																									9,000,000
Caelum [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																												$ 252,000	219,000
Licensing Agreements [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments to Acquire Intangible Assets																									$ 45,000	$ 150,000
Licensing Agreements [Member] | Effcon Laboratories nc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments to Acquire Intangible Assets																													300,000
Licensing Agreements [Member] | Dana Farber Cancer Institute [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process						$ 1,000,000
Licensing Agreements [Member] | City Of Hope [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Marketability Percentage Of Invested Capital																				44.50%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage																				30.00%
Share Price																				$ 0.097
Stock Issued During Period, Value, Other																				$ 48,500
Licensing Agreements [Member] | Mustang Bio, Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Stock Issued During Period, Shares, Issued for Services																														293,588
Stock Issued During Period, Value, Issued for Services																														$ 1,700,000
Share Price																														$ 5.73
Proceeds from Third Party Investors																		$ 10,000,000
Licensing Agreements [Member] | Cellvation Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Marketability Percentage Of Invested Capital																		40.20%
Stock Issued During Period, Shares, Issued for Services																		500,000
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent																		30.00%
Share Price																		$ 0.024
Stock Issued During Period, Value, Other																		$ 12,000
Payment of Upfront Fees																		$ 300,000
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners																		5.00%
Licensing Agreements [Member] | Cellvation Inc [Member] | Development Milestone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																		$ 6,200,000
Licensing Agreements [Member] | Cellvation Inc [Member] | Sale Millstone [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																		6,000,000
Licensing Agreements [Member] | Cellvation Inc [Member] | Minimum [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Additional Minimum Annual Royalty Payable																		50,000
Licensing Agreements [Member] | Cellvation Inc [Member] | Maximum [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Additional Minimum Annual Royalty Payable																		200,000
Licensing Agreements [Member] | IV Tramadol [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments to Acquire Intangible Assets																								$ 1,000,000
Payments for Fees																											$ 2,000,000
Licensing Agreements [Member] | Coronado SO Co, Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Marketability Percentage Of Invested Capital																												44.80%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage																												30.00%
Share Price																												$ 1.19
Licensing Agreements [Member] | Helocyte [Member] | Common Class A [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Noncash or Part Noncash Acquisition, Noncash Financial or Equity Instrument Consideration, Shares Issued																				8,333	500,000
Secondary License [Member] | Cellvation Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payment of Upfront Fees																		50,000
Revenue Recognition Milestone Method Payments Due																		300,000
Second TBI License [Member] | Cellvation Inc [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Minimum Annual Royalty Payable																		$ 100,000
AR CD123 License [Member] | City Of Hope [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition Milestone Method Payments Due																												$ 14,500,000
AR IL-13 License [Member] | City Of Hope [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																													500,000
Revenue Recognition Milestone Method Payments Due																												14,500,000
HER2 Technology License [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																												200,000	600,000
Payment of Upfront Fees													$ 600,000
Revenue Recognition Milestone Method Payments Due													14,900,000
Annual Maintenance Fee Payable													50,000
CS1 Technology License [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																												0	600,000
Payment of Upfront Fees			$ 600,000
Revenue Recognition Milestone Method Payments Due													14,900,000
Annual Maintenance Fee Payable													50,000
PSCA Technology License [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																													300,000
Payment of Upfront Fees			300,000
Revenue Recognition Milestone Method Payments Due													14,900,000
Annual Maintenance Fee Payable													$ 50,000
University of California [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																												200,000
Fred Hutchinson Cancer Research Center License [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																													300,000
Payment of Upfront Fees			300,000
Revenue Recognition Milestone Method Payments Due			39,100,000
Annual Maintenance Fee Payable			$ 50,000
Harvard College License [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																													300,000
Revenue Recognition, Sales and Marketing Milestone Method Payments Due																												16,700,000
MPS1 license [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition, Sales and Marketing Milestone Method Payments Due								$ 7,500,000
Revenue Recognition, Development Milestone Method Payments Due								$ 5,500,000
Revenue Recognition, Milestone Method, Extension Description								Extension for such milestones is $10,000 per milestone for the first year and $20,000 per milestone thereafter.
Nanadysferlin License [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition, Sales and Marketing Milestone Method Payments Due								$ 33,000,000
Revenue Recognition, Development Milestone Method Payments Due								$ 5,400,000
Revenue Recognition, Milestone Method, Extension Description								Extension for such milestones is $10,000 per milestone for the first year and $20,000 per milestone thereafter.
HLA-G License [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue Recognition, Sales and Marketing Milestone Method Payments Due								$ 42,000,000
Revenue Recognition, Development Milestone Method Payments Due								$ 5,400,000
Revenue Recognition, Milestone Method, Extension Description								Extension for such milestones is $10,000 per milestone for the first year and $20,000 per milestone thereafter.
CITY OF HOPE IV ICV License [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																													100,000
Manufacturing License [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Payments to Acquire Intangible Assets																												100,000
St Jude Childrens Research Hospital [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and Development in Process																													$ 1,000,000
Revenue Recognition Milestone Method Payments Due																												13,500,000
Additional Annual License fee																												1,000,000
Annual license fee																												$ 100,000