- Commitments and Contingencies - Narrative (Details) € in Millions, SFr in Millions, $ in Millions	1 Months Ended				12 Months Ended
	Jul. 31, 2016 USD ($)	Jul. 31, 2016 EUR (€)	Jun. 30, 2016 USD ($)	Jun. 30, 2016 CHF (SFr)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Rent expense					$ 3.5	$ 3.4	$ 2.8
Service agreement, period required for notice of non-renewal	24 months	24 months
Ypsomed
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Services agreement, term			3 years	3 years
Services agreement, renewal term			2 years	2 years
Services agreement, purchase period			3 years	3 years
Milestone payments and one-time capacity fee			$ 2.5	SFr 2.4
Vetter
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Services agreement, term			5 years	5 years
Services agreement, renewal term			2 years	2 years
Service agreement, period required for notice of non-renewal			2 years	2 years
Lonza
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Services agreement, term	6 years	6 years
Services agreement, renewal term	3 years	3 years
Collaborative arrangement, milestone payments annually	$ 3.4	€ 2.9
Collaborative arrangement, expected milestone payments	$ 17.2