Income Taxes - Net Operating Loss Carryforwards (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Net Operating Loss Carryforwards [Line Items]
Unrealized gross deferred tax assets attributable to excess tax benefits associated with stock-based compensation	$ 7.9
Federal
Net Operating Loss Carryforwards [Line Items]
Net operating losses	2.4
State
Net Operating Loss Carryforwards [Line Items]
Net operating losses	6.0
Foreign
Net Operating Loss Carryforwards [Line Items]
Net operating losses	0.1
SimpleDevices | Federal
Net Operating Loss Carryforwards [Line Items]
Net operating losses	2.3
Operating losses annual limitation	0.6
SimpleDevices | State
Net Operating Loss Carryforwards [Line Items]
Net operating losses	$ 3.8