Commitments and Contingencies - Future Minimum Lease Payments (Details) $ in Thousands	Jun. 30, 2018 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2018 (remaining 6 months) gross lease payment due	$ 952
2019 gross lease payment due	1,955
2020 gross lease payment due	1,234
2021 gross lease payment due	1,004
2022 gross lease payment due	946
Total gross lease payment due	6,091
2018 (remaining 6 months) sublease income	(258)
2019 sublease income	(576)
2020 sublease income	(148)
2021 sublease income	0
2022 sublease income	0
Total sublease income	(982)
2018 (remaining 6 months) net lease payments	694
2019 net lease payments	1,379
2020 net lease payments	1,086
2021 net lease payments	1,004
2022 net lease payments	946
Total net lease payments	$ 5,109