Revenue (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Jan. 31, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Remaining performance obligation	$ 31,000,000.0	$ 31,000,000.0		$ 31,000,000.0
Revenues		299,000	$ 0	357,000	$ 278,000
Deferred revenue, current portion	12,255,000	12,255,000		12,255,000		$ 7,911,000
Deferred revenue, net of current portion	74,295,000	74,295,000		74,295,000		47,948,000
Mylan
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue	30,000,000
Non-refundable upfront payment	60,000,000	60,000,000		60,000,000
Contingent payments	70,000,000	70,000,000		70,000,000
Revenue maximum for receipt of tiered milestone payments				225,000,000
Remaining performance obligation	106,600,000	106,600,000		106,600,000
Shanghai Fosun Pharmaceutical Industrial Development Co., Ltd.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contingent payments							$ 229,500,000
Contract with customer, liability, revenue recognized		0	0	0	0
Product
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue				100,000
Development Services
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenues		300,000	$ 0	300,000	$ 300,000
Deferred revenue, current portion	12,200,000	12,200,000		12,200,000		7,900,000
Deferred revenue, net of current portion	$ 43,300,000	$ 43,300,000		$ 43,300,000		$ 18,000,000.0