Commitments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Commitments
Rental expense	$ 200	$ 200	$ 500	$ 400
Future minimum payments for operating leases
Remainder of 2016	115		115
2017	420		420
2018	425		425
2019	419		419
2020 and thereafter	1,340		1,340
Total	2,719		2,719
Future minimum payments for other commitments
Remainder of 2016	2,653		2,653
2017	4,121		4,121
2018	2,539		2,539
2019	1,256		1,256
2020 and thereafter	631		631
Total	11,200		11,200
Future minimum payments for operating leases and other commitments
Remainder of 2016	2,768		2,768
2017	4,541		4,541
2018	2,964		2,964
2019	1,675		1,675
2020 and thereafter	1,971		1,971
Total	$ 13,919		$ 13,919