Stock incentive plan and stock-based compensation (Details 2) (USD $)	3 Months Ended
Mar. 31, 2014
Class of Warrant or Right [Line Items]
Number of warrants - Warrants outstanding at December 31, 2013	920,825
Number of warrants - Issued	0
Number of warrants - Exercised	0
Number of warrants - Expired	0
Number of warrants - Warrants outstanding at March 31, 2014	920,825
Weighted average exercise price - Warrants outstanding at December 31, 2013	$ 3.46
Weighted average exercise price - Issued	$ 0
Weighted average exercise price - Exercised	$ 0
Weighted average exercise price - Expired	$ 0
Weighted average exercise price - Warrants outstanding at March 31, 2014	$ 3.46

The number of share based compensation arrangement by share based payment award warrants exercised.

No definition available.

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The number of share based compensation arrangement by share based payment award warrants expired.

No definition available.

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The number of share based compensation arrangement by share based payment award warrants issued.

No definition available.

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The number of share based compensation arrangement by share based payment award warrants outstanding.

No definition available.

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Represents share based compensation arrangement by share based payment award weighted average exercise price warrants exercised.

No definition available.

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Represents share based compensation arrangement by share based payment award weighted average exercise price warrants expired.

No definition available.

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Represents share based compensation arrangement by share based payment award weighted average exercise price warrants issued.

No definition available.

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Represents share based compensation arrangement by share based payment award weighted average exercise price warrants outstanding.

No definition available.

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