Schedule of Revenue from Collaborations and Services (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	$ 75,442	$ 65,144
Collaborations and services
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	36,274	32,820
Collaborations and services | License Agreement | United Therapeutics Corporation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	34,145	32,213
Collaborations and services | Commercial Supply Agreement | United Therapeutics Corporation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	267
Collaborations and services | Co-Promotion Agreement | Vertice Pharma LLC
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	1,147
Collaborations and services | Collaboration and License Agreement | Receptor CLA
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	245	250
Collaborations and services | License and Distribution Agreement | Cipla Ltd
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	147	147
Collaborations and services | Other
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	$ 323
Collaborations and services | Research Agreement | United Therapeutics Corporation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services		$ 210