Commitments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Commitments
Rental expense	$ 200	$ 100
Future minimum payments for operating leases
Remainder of 2016	111
2017	387
2018	391
2019	352
2020 and thereafter	1,303
Total	2,544
Future minimum payments for other commitments
Remainder of 2016	7,052
2017	3,415
2018	2,539
2019	1,256
2020 and thereafter	631
Total	14,893
Future minimum payments for operating leases and other commitments
Remainder of 2016	7,163
2017	3,802
2018	2,930
2019	1,608
2020 and thereafter	1,934
Total	$ 17,437