Commitments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Commitments
Rental expense	$ 200	$ 100	$ 300	$ 300
Future minimum payments for operating leases
Remainder of 2016	82		82
2017	386		386
2018	390		390
2019	378		378
2020 and thereafter	1,330		1,330
Total	2,566		2,566
Future minimum payments for other commitments
Remainder of 2016	5,822		5,822
2017	3,508		3,508
2018	2,539		2,539
2019	1,256		1,256
2020 and thereafter	631		631
Total	13,756		13,756
Future minimum payments for operating leases and other commitments
Remainder of 2016	5,904		5,904
2017	3,894		3,894
2018	2,929		2,929
2019	1,634		1,634
2020 and thereafter	1,961		1,961
Total	$ 16,322		$ 16,322