5. Shareholders' equity (Details) - Changes in Shareholders' Equity - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Changes in Shareholders' Equity [Abstract]
Balance at December 31, 2014			$ 25,394
Balance at September 30, 2015	$ 25,609		25,609
Net income	$ 1,028	$ 50	2,560	$ 619
Share-based compensation expense			377	442
Issuance of deferred stock units, net of relinquishments			121
Proceeds from issuance of shares from exercise of stock options			42
Incremental tax benefits from stock options exercised			2
Foreign currency translation adjustment			(4)
Dividends declared and paid on common stock			(1,863)
Purchase of common stock for treasury			$ (1,020)	$ (826)