Strategic Alliances (Details) - USD ($)						1 Months Ended			3 Months Ended		87 Months Ended
	Sep. 14, 2021	Jul. 06, 2021	Jun. 18, 2021	May 05, 2020	Oct. 21, 2019	Apr. 30, 2022	May 31, 2016	Jan. 31, 2015	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues									$ 329,219,000	$ 545,165,000
Milestone revenue recognized									4,000
LeaderMed | LeaderMed Joint Venture | Corporate Joint Venture
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Ownership interest in joint venture (as a percent)	47.00%
Initial investment in joint venture	$ 11,000,000
Ownership percentage by related parties (as a percent)	53.00%
CAMP4
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment (in shares)		3,373,008
Outstanding shares (as a percent)		9.00%
Period following first commercial sale in a country		10 years
Nicoya
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment from development and license agreement			$ 5,000,000
Period after first commercial sale			10 years
Pfizer | Products
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum milestone payments								$ 275,000,000
Annual height velocity at point in time					12 months
Initial upfront payment								295,000,000
Additional milestone payment								275,000,000
Milestone revenue recognized											$ 0
Pfizer | Products | Subsequent Event
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payments						$ 85,000,000
Minimum | Pfizer | Products
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payments								20,000,000
Maximum | Pfizer | Products
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payments								$ 90,000,000
Phase Three Initiation | Nicoya
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment from development and license agreement			$ 5,000,000
Regulatory and Development | Nicoya
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Milestone payment from development and license agreement			$ 115,000,000
Transfer of intellectual property and other
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues									5,962,000	4,269,000
Transfer of intellectual property and other | Products
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues				$ 3,000,000
Transfer of intellectual property and other | LeaderMed | LeaderMed Joint Venture | Corporate Joint Venture
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues	$ 1,000,000								1,000,000
Transfer of intellectual property and other | CAMP4
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues		$ 1,500,000
Transfer of intellectual property and other | VFMCRP | Products
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues									3,000,000
Transfer of intellectual property and other | Pfizer | Products
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues									2,200,000	2,800,000
Dravet Syndrome Products | CAMP4
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development milestone payments		3,500,000
Sales milestone payments		$ 90,000,000
Development milestone payments (in shares)		5,782,299
Non-Dravet Syndrome Products | CAMP4
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Development milestone payments		$ 4,000,000
Sales milestone payments		$ 90,000,000
Development milestone payments (in shares)		1,082,248
Products
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues									$ 36,658,000	$ 33,945,000
Regulatory Milestones | EirGen Pharma Limited
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum milestone payments				17,000,000
Sales Milestones | EirGen Pharma Limited
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum milestone payments				$ 207,000,000
Exclusive Option | VFMCRP
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum milestone payments							$ 555,000,000