13. Income taxes (Details) - Income Tax Provision Components (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current:
Federal	$ 1,479	$ 1,973	$ 1,695
State	38	46	74
Foreign	33	40	44
	1,550	2,059	1,813
Deferred:
Federal	80	(116)	448
State	(34)	21	71
	46	(95)	519
Income tax provision	$ 1,596	$ 1,964	$ 2,332