401(k) Plan (Details) (401(k) Benefit Plan [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
401(k) Benefit Plan [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	50.00%
Company contributions to benefit plan	$ 0.9	$ 0.7	$ 0.6