Stock-based compensation (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2012
Outstanding at the beginning of period -Options	378,394
Granted-Options	15,813
Exercised-Options	(1,384)
Forfeited/expired-Options	(77,169)
Outstanding at the ending of period -Options	315,654
Exercisable-Options	199,300
Outstanding-Weighted Average Exercise Price at the beginning of period - Options	$ 14.91
Granted-Weighted Average Exercise Price	$ 7.13
Exercised-Weighted Average Exercise Price	$ 6.46
Forfeited/expired-Weighted Average Exercise Price	$ 18.99
Outstanding-Weighted Average Exercise Price at the ending of period - Options	$ 13.56
Exercisable-Weighted Average Exercise Price	$ 15.34
Outstanding-Weighted Average Remaining Contractual Life (Years)	2 years 22 days
Exercisable-Weighted Average Remaining Contractual Life (Years)	1 year 2 months 27 days
Outstanding-Aggregate Intrinsic Value	$ 0	[1]
Exercisable-Aggregate Intrinsic Value	$ 0	[1]

[1] The intrinsic value of a stock option represents the amount by which the fair value of the underlying stock, measured by reference to the closing price of the common shares of $7.40 on the Nasdaq Global Select Market on December 31, 2012, exceeds the exercise price of the option.