Commitments and Contingencies (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Additional period for which the entity may elect to extend the term of the lease	5 years
Additional tenant improvement allowance	$ 2,100,000
Tenant improvement allowance utilized and included in fixed assets and deferred rent	79,000	$ 0	$ 200,000
Amount available for tenant improvements	400,000
Rent expense	2,700,000	$ 2,700,000	$ 2,600,000
Future minimum lease payments under non-cancelable operating leases
2018	3,349,000
2019	5,249,000
Thereafter	454,000
Total	9,052,000
Rune HealthCare Limited
Future minimum lease payments under non-cancelable operating leases
Milestone payments due	0
Afecta Pharmaceuticals Inc | Maximum
Future minimum lease payments under non-cancelable operating leases
Potential maximum milestone payments payable	$ 300,000