Stockholders' Equity (Details 2) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended		12 Months Ended
	Jan. 03, 2013	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Restricted Stock-Based Compensation
Number of days of average trailing stock price used to calculate number of shares of common stock granted		10 days
2011 Plan | Restricted stock
Restricted Stock-Based Compensation
Number of shares granted	106,268
Fair value of shares granted	$ 1.9
Fair value of shares granted (in dollars per share)	$ 18.11
Non-cash compensation expense recognized		0.2	0.1
Unrecognized compensation expense for remaining life of the awards		3.1		1.5
Number of shares vested		33,366		16,161
Fair value of shares vested		$ 0.5		$ 0.2
Shares forfeited		11,540		1,559