| Collaborative, Licensing and Other Arrangements - NIAID - Additional Information (Details) - USD ($) | 1 Months Ended | 3 Months Ended | |
|---|---|---|---|
| Oct. 31, 2011 | Mar. 31, 2017 | Mar. 31, 2016 | |
| Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | |||
| Recognition of revenue | $ 110,000 | $ 1,471,000 | |
| National Institute of Allergy and Infectious Diseases "NIAID" [Member] | Arrangement with Governmental Agency 1 [Member] | |||
| Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] | |||
| Total contract amount awarded | $ 28,000,000 | ||
| Contractual term | 5 years | ||
| Recognition of revenue | $ 0 | $ 1,100,000 | |
| X | ||||||||||
| 
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
 | 
| X | ||||||||||
| 
- Definition Amount of revenue earned from products sold or services provided under the terms of a contract, including, but not limited to, government contracts and construction contracts, classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Definition Contractual term of collaborative, licensing and other arrangements, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available. 
 | 
| X | ||||||||||
| 
- Definition Maximum revenue from contract. No definition available. 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 |