Commitments and Contingencies - Leases (Details) $ in Thousands	1 Months Ended		9 Months Ended
	Mar. 31, 2017 USD ($) a item	Jan. 31, 2017 USD ($) a	Sep. 30, 2017 USD ($) a
Remaining commitments
2017			$ 29
2018			459
2019			559
2020			$ 629
Shoal Point Leases
Commitments and Contingencies
Area available for lease | a		1,000	1,000
Term of lease agreement		36 months
Extension of term of contract		12 months
First threshold period		12 months
Additional cost		$ 0
Potential aggregate payments for early terminations		$ 50
Remaining commitments
2018			$ 400
2019			500
2020			600
The Brownsville Lease
Commitments and Contingencies
Area available for lease | a	10
Term of lease agreement	8 months
Number of times agreement can be renewed | item	6
Extension of term of contract	6 months
Potential aggregate payments for early terminations	$ 0
Remaining commitments
2017			29
2018			59
2019			59
2020			$ 29