Stock incentive plans (Details 6) (RSU, USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Number of Shares
Granted (in shares)	799,000
Vested (in shares)	(6,000)
Canceled/forfeited (in shares)	(40,000)
Nonvested at the end of the period (in shares)	753,000
Weighted Average Grant-Date Fair Value
Granted (In dollars per share)	$ 6.21
Vested (In dollars per share)	$ 6.39
Canceled/forfeited (In dollars per share)	$ 6.05
Nonvested at the end of the period (In dollars per share)	$ 6.22
Total stock-based compensation expense	$ 2,750
Weighted average period over which unrecognized compensation expense is expected to be recognized	1 year 4 months 24 days
Executive and non executive
Stock incentive plans
Vesting period	2 years
Vesting percentage when the individual completes 12 months of continuous service	50.00%
Continuous service period of individual	12 months
Vesting percentage on a quarterly basis	50.00%
Existing members
Stock incentive plans
Vesting period	1 year
New members
Stock incentive plans
Vesting period	4 years
Annual vesting percentage	25.00%