Income Taxes - Net Operating Loss Carryforwards (Details) $ in Millions	Dec. 31, 2016 USD ($)
Operating Loss Carryforwards [Line Items]
Unrealized gross deferred tax assets attributable to excess tax benefits associated with stock-based compensation	$ 3.5
Federal
Operating Loss Carryforwards [Line Items]
Net operating losses	0.6
Federal | SimpleDevices
Operating Loss Carryforwards [Line Items]
Operating losses annual limitation	0.6
State
Operating Loss Carryforwards [Line Items]
Net operating losses	2.1
Foreign
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 0.2