Schedule of Revenue from Collaborations and Services (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	$ 22,211	$ 15,352	$ 62,927	$ 46,701
Collaborations and services
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	12,458	8,077	35,099	24,441
Collaborations and services | License Agreement | United Therapeutics Corporation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	12,313	7,978	33,475	23,934
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	31	63	206	188
Collaborations and services | License and Distribution Agreement | Cipla Ltd
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	37	$ 36	110	108
Collaborations and services | Research Agreement | United Therapeutics Corporation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services				$ 211
Collaborations and services | Other
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue from collaborations and services	$ 77		$ 161