Subsequent Events (Details) - Subsequent Event - HealthCare Royalty Partners $ in Millions	May 10, 2018 USD ($)
Subsequent Event [Line Items]
Proceeds from royalty agreement	$ 125
Maximum potential royalty payout	180.00%
Period One
Subsequent Event [Line Items]
Maximum potential royalty payout	10.00%
Period Two
Subsequent Event [Line Items]
Increase in maximum potential payout percent	4.00%
Payout Period
Subsequent Event [Line Items]
Increase in maximum potential payout percent	4.00%