Commitments and Contingencies - License Agreement with Chimerix, Inc. (Details) - USD ($)	Dec. 17, 2014	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016
Series B convertible preferred stock
Agreement
Convertible preferred stock, stated value (in dollars per share)	$ 10.00	$ 10.00		$ 10.00
Common Stock
Agreement
Shares converted, Common Stock		23,900,000	1,100,000
Chimerix, Inc.
Agreement
Amounts accrued related to the payments		$ 0
License Agreement | Chimerix, Inc.
Agreement
Maximum payments to be made for clinical, regulatory and initial commercial milestones	$ 20,000,000
Minimum prior written notice period in order to terminate agreement	60 days
Cost of license classified as research and development expense	$ 1,200,000
License Agreement | Chimerix, Inc. | Preferred Stock | Series B convertible preferred stock
Agreement
Shares issued in connection with license (in shares)	120,000
Fair value of preferred stock issued	$ 1,200,000
License Agreement | Chimerix, Inc. | Common Stock
Agreement
Shares converted, Common Stock		1,100,000