Stock-Based Compensation (Details Textual) - USD ($) $ in Millions				12 Months Ended
	May 25, 2016	Dec. 30, 2013	Apr. 12, 2010	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	May 29, 2010
Stock Based Compensation Details [Line Items]
Shares of common stock outstanding				53,400,281	53,148,441
Intrinsic value of options outstanding				$ 4.7	$ 11.5	$ 17.4
Intrinsic value of options exercisable				4.7	11.3	16.3
Intrinsic value of options exercised				0.4	0.3	0.6
Unrecognized compensation costs				2.3
General and Administrative Expense
Stock Based Compensation Details [Line Items]
Stock option based expenses				$ 2.3	$ 2.3	$ 1.7
Director Stock Option Plan - 1999
Stock Based Compensation Details [Line Items]
Shares approved and authorized (in shares)					1,975,000
Number of options granted (in shares)					2,634,798
Number of options forfeited (in shares)					807,782
Vesting period				1 year
Maximum term				10 years
Number of options outstanding (in shares)				500,000	650,000
Shares available for grant					147,984
Nineteen Ninety Nine Stock Incentive Plan
Stock Based Compensation Details [Line Items]
Shares approved and authorized (in shares)				3,200,000
Number of options granted (in shares)				2,892,500
Vesting period				4 years
Maximum term				10 years
Percent of FMV options granted				100.00%
Service period				1 year
Plan 2009
Stock Based Compensation Details [Line Items]
Shares approved and authorized (in shares)								5,000,000
Number of options outstanding (in shares)				3,038,634
Additional shares authorized (in shares)			2,000,000
Maximum number of shares to any individual (in shares)				1,000,000
Shares of common stock outstanding				1,422,020	1,341,746
Options transferred				156,169	92,883
Plan 2016
Stock Based Compensation Details [Line Items]
Shares approved and authorized (in shares)	2,000,000
Shares available for grant				1,526,857	1,981,867
Maximum number of shares to any individual (in shares)	1,000,000
Shares of common stock outstanding				20,000	20,000
Plan 2016, Plan 2009 And Director Plan
Stock Based Compensation Details [Line Items]
Number of options outstanding (in shares)				4,299,810	4,105,369
Jason Grenfell-Gardner
Stock Based Compensation Details [Line Items]
Shares granted (in shares)		325,000
Restricted Stock Units (RSUs)
Stock Based Compensation Details [Line Items]
RSUs outstanding				188,629	179,900	182,750
Shares granted (in shares)				93,468	58,068
Restricted Stock Units (RSUs) | Plan 2009
Stock Based Compensation Details [Line Items]
RSUs outstanding				99,626	179,900
Restricted Stock Units (RSUs) | Plan 2016
Stock Based Compensation Details [Line Items]
RSUs outstanding				89,003
Restricted Stock
Stock Based Compensation Details [Line Items]
RSUs outstanding						0	108,334
Shares granted (in shares)						32,500
Stock option based expenses				$ 1.0	$ 0.8	$ 0.6
Unrecognized compensation costs				$ 0.7
Common Stock | Plan 2009
Stock Based Compensation Details [Line Items]
Number of options outstanding (in shares)					3,216,369
Common Stock | Plan 2016
Stock Based Compensation Details [Line Items]
Number of options outstanding (in shares)				761,176	239,000
Minimum | Restricted Stock
Stock Based Compensation Details [Line Items]
Vesting period				1 year
Maximum | Restricted Stock
Stock Based Compensation Details [Line Items]
Vesting period				3 years