Revenue Recognition - Additional Information (Detail) - USD ($)	1 Months Ended					3 Months Ended								12 Months Ended
	Dec. 31, 2016	Oct. 31, 2016	Mar. 31, 2016	Feb. 29, 2016	Jul. 31, 2014	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Costs to obtain or fulfill the contract capitalized						$ 0								$ 0
Collaboration and license revenue														116,640,000	$ 40,130,000	$ 22,546,000
Contract liabilities						5,518,000				$ 6,335,000				5,518,000	6,335,000
Unbilled - collaboration and license revenue						3,783,000				9,880,000				3,783,000	9,880,000
Deferred revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contract liabilities						5,518,000				6,335,000				5,518,000	6,335,000
BMS and Pfizer | 2016 Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable upfront fee				$ 15,000,000.0
Contingent payment receivable upon achievement of regulatory events				20,000,000.0
Contingent payment receivable upon achievement of annual net sales volumes				$ 70,000,000.0
BMS and Pfizer | 2016 Agreement | Minimum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalties entitle to receive under agreement				5.00%
BMS and Pfizer | 2016 Agreement | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalties entitle to receive under agreement				15.00%
Daiichi Sankyo, Inc ("Daiichi") | 2014 Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront fee					$ 15,000,000.0
Milestone payments of development and regulatory event					20,000,000.0
Contingent payment receivable upon achievement					$ 5,000,000.0
Daiichi Sankyo, Inc ("Daiichi") | October 2016 Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront fee		$ 15,000,000.0
Milestone payments of development and regulatory event		$ 2,500,000
Percentage of consideration received under agreement		1.00%
Contingent payment receivable upon achievement of annual net sales volumes		$ 8,000,000.0
Contingent payment receivable upon achievement		$ 10,000,000.0
Daiichi Sankyo, Inc ("Daiichi") | March 2016 Agreement | Ethnic Sensitivity Study
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reimbursement of costs and expenses percentage			33.00%
Daiichi Sankyo, Inc ("Daiichi") | March 2016 Agreement | Minimum | Edoxaban
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reimbursement of costs and expenses percentage			33.00%
Daiichi Sankyo, Inc ("Daiichi") | March 2016 Agreement | Maximum | Edoxaban
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reimbursement of costs and expenses percentage			100.00%
Bayer Pharma AG | 2016 Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront fee				$ 5,000,000.0
Contingent payment receivable upon achievement				10,000,000.0
Reduced contingent payment receivable upon achievement				$ 7,000,000.0
Bayer Pharma AG | 2016 Agreement | Ethnic Sensitivity Study
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reimbursement of costs and expenses percentage				33.00%
Bayer Pharma AG | 2016 Agreement | Minimum | Rivaroxaban
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reimbursement of costs and expenses percentage				33.00%
Bayer Pharma AG | 2016 Agreement | Maximum | Rivaroxaban
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reimbursement of costs and expenses percentage				100.00%
Dermavant Sciences GmbH (“Dermavant”)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalties entitle to receive under agreement	9.00%
Upfront payment received	$ 8,800,000
Contingent development and regulatory milestones to be received	36,300,000
Dermavant Sciences GmbH (“Dermavant”) | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Commercial milestone payments on worldwide annual net sales to be received	$ 100,000,000.0
Distribution Fees And Reserves For Cargebacks And Product Returns [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reduction to revenue														20,600,000	3,600,000
Royalty
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration and license revenue														0
Collaboration and License Revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration and license revenue						873,000	$ 1,056,000	$ 1,260,000	$ 1,807,000	1,228,000	$ 7,001,000	$ 1,746,000	$ 6,038,000	4,996,000	16,013,000	22,546,000
Collaboration and License Revenue | Dermavant Sciences GmbH (“Dermavant”)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration and license revenue														0	0	3,800,000
Accounting Standards Update 2014-09 | BMS and Pfizer | 2016 Agreement | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price														10,600,000
Upfront payment						15,000,000.0								15,000,000.0
Accounting Standards Update 2014-09 | BMS and Pfizer | 2016 Agreement | Topic 606 | Deferred revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contract liabilities						4,800,000				6,300,000				4,800,000	6,300,000
Accounting Standards Update 2014-09 | Daiichi Sankyo, Inc ("Daiichi") | 2016 Agreement | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Costs to obtain or fulfill the contract capitalized						0				0				0	0
Transaction price														16,400,000
Upfront payment						5,000,000.0								5,000,000.0
Estimated variable consideration transaction price						6,900,000								6,900,000
Regulatory milestone payments														10,000,000.0
Accounting Standards Update 2014-09 | Daiichi Sankyo, Inc ("Daiichi") | 2016 Agreement | Topic 606 | Ethnic Sensitivity Study
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Estimated variable consideration transaction price						4,500,000								4,500,000
Accounting Standards Update 2014-09 | Daiichi Sankyo, Inc ("Daiichi") | 2016 Agreement | Topic 606 | Deferred revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Unbilled - collaboration and license revenue						1,600,000				3,100,000				1,600,000	3,100,000
Accounting Standards Update 2014-09 | Daiichi Sankyo, Inc ("Daiichi") | 2014 and October 2016 Amendment | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price														34,000,000.0
Costs to obtain or fulfill the contract						0				0				0	0
Upfront payment						22,000,000.0								22,000,000.0
Milestones already received on achieving performance obligations														12,000,000.0
Milestone payments eligible for achievement														5,500,000
Accounting Standards Update 2014-09 | Daiichi Sankyo, Inc ("Daiichi") | 2014 and October 2016 Amendment | Topic 606 | Deferred revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contract liabilities						700,000								700,000
Unbilled - collaboration and license revenue										1,400,000					1,400,000
Accounting Standards Update 2014-09 | Bayer Pharma, AG ('Bayer") and Janssen Pharmaceuticals, Inc. ("Janssen") | 2014 Agreement | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Costs to obtain or fulfill the contract capitalized						0				0				0	0
Accounting Standards Update 2014-09 | Bayer Pharma, AG ('Bayer") and Janssen Pharmaceuticals, Inc. ("Janssen") | 2014 Agreement | Topic 606 | Deferred revenue
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Unbilled - collaboration and license revenue										2,000,000.0					2,000,000.0
Accounting Standards Update 2014-09 | Bayer Pharma AG | 2016 Agreement | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price														16,400,000
Costs to obtain or fulfill the contract						0				0				0	0
Upfront payment						5,000,000.0								5,000,000.0
Milestone payments eligible for achievement														10,000,000.0
Unbilled - collaboration and license revenue						2,200,000				$ 3,500,000				2,200,000	3,500,000
Estimated variable consideration transaction price						6,900,000								6,900,000
Accounting Standards Update 2014-09 | Bayer Pharma AG | 2016 Agreement | Topic 606 | Ethnic Sensitivity Study
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Estimated variable consideration transaction price						4,500,000								4,500,000
Accounting Standards Update 2014-09 | Collaboration and License Revenue | BMS and Pfizer | 2016 Agreement | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration and license revenue														(1,100,000)	800,000	3,100,000
Accounting Standards Update 2014-09 | Collaboration and License Revenue | BMS and Pfizer | 2014 Agreement | Maximum | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration and license revenue														100,000	1,500,000	1,800,000
Accounting Standards Update 2014-09 | Collaboration and License Revenue | Daiichi Sankyo, Inc ("Daiichi") | 2016 Agreement | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration and license revenue														2,400,000	3,500,000	1,100,000
Accounting Standards Update 2014-09 | Collaboration and License Revenue | Daiichi Sankyo, Inc ("Daiichi") | 2014 and October 2016 Amendment | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration and license revenue														900,000	2,900,000	6,400,000
Accounting Standards Update 2014-09 | Collaboration and License Revenue | Bayer Pharma, AG ('Bayer") and Janssen Pharmaceuticals, Inc. ("Janssen") | 2014 Agreement | Maximum | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration and license revenue														100,000	4,100,000	5,400,000
Accounting Standards Update 2014-09 | Collaboration and License Revenue | Bayer Pharma AG | 2016 Agreement | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration and license revenue														2,700,000	$ 3,400,000	$ 1,000,000.0
Accounting Standards Update 2014-09 | New Drug Application | BMS and Pfizer | 2016 Agreement | Topic 606
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Estimated variable consideration transaction price														4,300,000
Accounting Standards Update 2014-09 | New Drug Application | BMS and Pfizer | 2016 Agreement | Topic 606 | Japan
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment						$ 5,000,000.0								5,000,000.0
Accounting Standards Update 2014-09 | Phase Four Clinical Trial | BMS and Pfizer | 2016 Agreement | Topic 606 | Japan
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Costs on clinical trial														700,000
Decrease in transaction price														$ 14,400,000