Commitments and Contingencies - Additional Information (Details) $ in Millions |
3 Months Ended | |
|---|---|---|
|
Mar. 31, 2018
USD ($)
Lease
|
Mar. 31, 2017
USD ($)
|
|
| Commitments And Contingencies Disclosure [Abstract] | ||
| Number of non-cancelable operating leases | Lease | 1 | |
| Operating leases, expiration date | Oct. 31, 2022 | |
| Rent expense, operating lease | $ | $ 0.5 | $ 0.5 |