Summary of Significant Accounting Policies - Basis of presentation and credit risk (Details) $ in Thousands |
3 Months Ended | 11 Months Ended | 12 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2016
USD ($)
|
Sep. 30, 2016
USD ($)
|
Jun. 30, 2016
USD ($)
|
Mar. 31, 2016
USD ($)
|
Dec. 31, 2015
USD ($)
|
Sep. 30, 2015
USD ($)
|
Jun. 30, 2015
USD ($)
|
Mar. 31, 2015
USD ($)
|
Dec. 31, 2014
USD ($)
|
Dec. 31, 2016
USD ($)
segment
item
|
Dec. 31, 2015
USD ($)
|
|
| Summary of Significant Accounting Policies | |||||||||||
| Accumulated deficit | $ (67,871) | $ (31,496) | $ (67,871) | $ (31,496) | |||||||
| Cash, cash equivalents and marketable securities | 134,900 | $ 134,900 | |||||||||
| Concentrations of Credit Risk and Other Risks and Uncertainties | |||||||||||
| Number of highly credit qualified financial institutions | item | 2 | ||||||||||
| Net loss | $ (11,086) | $ (10,297) | $ (8,645) | $ (6,347) | $ (6,039) | $ (3,151) | $ (20,232) | $ (1,913) | $ (161) | $ (36,375) | (31,335) |
| Cash in operations | $ (96) | $ (27,857) | $ (11,328) | ||||||||
| Segments | |||||||||||
| Number of operating segments | segment | 1 | ||||||||||