Commitments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Future minimum commitments under non-cancelable operating lease arrangements [Abstract]
2014	$ 968
2015	830
2016	539
2017	515
2018	442
2019 and thereafter	101
Total commitments	3,395
Operating lease expense	1,090	815	644
Future commitments under unconditional purchase obligations [Abstract]
2014	2,171
2015	598
2016	0
2017	0
2018	0
Total commitments	$ 2,769