Summary of significant accounting policies (Details 9) (Restricted stock awards, USD $)	12 Months Ended	3 Months Ended	1 Months Ended	0 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Feb. 28, 2014	Jul. 26, 2011	Aug. 16, 2014	Jun. 27, 2014	Mar. 10, 2014	Nov. 15, 2013	Jul. 26, 2011	Aug. 15, 2014	Jun. 27, 2014	Nov. 15, 2013	Mar. 10, 2014	Dec. 31, 2013
Long-term incentive restricted stock agreements assumptions and vesting requirements
Stock granted (in shares)	930,830
Number of shares outstanding	1,641,585													1,765,333
Board of Directors, Directors
Long-term incentive restricted stock agreements assumptions and vesting requirements
Stock granted (in shares)		200,000
Fair value of awards granted		$ 500,000
Requisite service period		12 months
Philip Beck | Board of Directors, Chairman
Long-term incentive restricted stock agreements assumptions and vesting requirements
Percentage of shares repurchased upon exercise of the repurchase option (as a percent)			35.00%
Number of shares repurchased upon exercise of the repurchase option (in shares)			320,250
Repurchase option price (in dollars per share)			$ 1.00
Number of shares outstanding			594,750
Restricted stock with performance and market conditions | Philip Beck | Board of Directors, Chairman
Long-term incentive restricted stock agreements assumptions and vesting requirements
Stock granted (in shares)				915,000
Number of separate tranches in which stock-based award will vest				4					4
Restricted stock with performance conditions
Long-term incentive restricted stock agreements assumptions and vesting requirements
Fair value				300,000					300,000
Restricted stock with performance conditions | Restricted stock with performance conditions, tranche 1
Long-term incentive restricted stock agreements assumptions and vesting requirements
Stock granted (in shares)				198,250
Fair value				71,370					71,370
Restricted stock with performance conditions | Restricted stock with performance conditions, tranche 1 | Minimum
Long-term incentive restricted stock agreements assumptions and vesting requirements
Adjusted EBITDA per fully diluted share when upon achievement shares will vest (in dollars per share)				0.36					$ 0.36
Restricted stock with performance conditions | Restricted stock with performance conditions, tranche 2
Long-term incentive restricted stock agreements assumptions and vesting requirements
Stock granted (in shares)				30,550
Fair value				19,552					19,552
Restricted stock with performance conditions | Restricted stock with performance conditions, tranche 2 | Minimum
Long-term incentive restricted stock agreements assumptions and vesting requirements
Adjusted EBITDA per fully diluted share when upon achievement shares will vest (in dollars per share)				0.64					$ 0.64
Restricted stock with performance conditions | Restricted stock with performance conditions, tranche 3
Long-term incentive restricted stock agreements assumptions and vesting requirements
Stock granted (in shares)				304,850
Fair value				216,444,000,000					216,444,000,000
Restricted stock with performance conditions | Restricted stock with performance conditions, tranche 3 | Minimum
Long-term incentive restricted stock agreements assumptions and vesting requirements
Adjusted EBITDA per fully diluted share when upon achievement shares will vest (in dollars per share)				0.71					$ 0.71
Restricted stock with market conditions
Long-term incentive restricted stock agreements assumptions and vesting requirements
Fair value				3,640					3,640
Valuation assumptions used for estimated fair value on grant date
Expected life					1 year 4 months 17 days	1 year 6 months 4 days	1 year 2 months 19 days	1 year 4 months 13 days	5 years 3 months 18 days
Expected volatility (percentage)					26.54%	26.72%	27.50%	27.30%	31.68%
Risk-free interest rate (percentage)					0.25%	0.17%	0.23%	0.23%	2.04%
Restricted stock with market conditions | 2012 Equity Incentive Plan
Long-term incentive restricted stock agreements assumptions and vesting requirements
Stock granted (in shares)		5,735								250,000	325,000
Fair value		1,023
Restricted stock with market conditions | Carl Williams | Director Chief Executive Officer and President | 2012 Equity Incentive Plan
Long-term incentive restricted stock agreements assumptions and vesting requirements
Stock granted (in shares)												200,000
Fair value								2,647				2,647
Restricted stock with market conditions | Philip Beck | Board of Directors, Chairman | 2012 Equity Incentive Plan
Long-term incentive restricted stock agreements assumptions and vesting requirements
Stock granted (in shares)													150,000
Fair value							3,000						3,000
Restricted stock with market conditions | Minimum | 2012 Equity Incentive Plan
Valuation assumptions used for estimated fair value on grant date
Closing price of common stock as reported on NASDAQ (in dollars per share)						6.00	6.00	6.00		6.00	6.00	$ 6.00	$ 6.00
Number of consecutive trading days during which the closing price of the entity's common stock on the NASDAQ stock market must exceed the specified price in order for the award to vest						30	30	30		30	30	30	30
Minimum per share consideration for change in control for shares to vest (in dollars per share)						6.00	6.00	6.00		6.00	6.00	$ 6.00	$ 6.00
Fair market value of stock immediately following change of control transaction, upon achievement of which share will be vested (in dollars per share)						6.00	6.00	6.00		6.00	6.00	$ 6.00	$ 6.00
Restricted stock with market conditions | Restricted stock with market conditions, tranche 4
Long-term incentive restricted stock agreements assumptions and vesting requirements
Stock granted (in shares)				61,100
Fair value				3,640					$ 3,640
Number of consecutive trading days during which the fair market value of the entity's common stock must exceed the specified price in order for the award to vest				75
Restricted stock with market conditions | Restricted stock with market conditions, tranche 4 | Minimum
Long-term incentive restricted stock agreements assumptions and vesting requirements
Fair market value of stock upon achievement of which share will be vested (in dollars per share)				12.00					$ 12.00