Financial Instruments - Fair Value and Notional Principal Amounts of Outstanding or Unsettled Derivative Instruments (Details) - Not Designated as Hedging Instrument - Foreign Exchange-forward Contracts - Accrued expenses and other current liabilities	Jun. 30, 2018 USD ($)	[1]
Derivatives Fair Value [Line Items]
Fair Value of Derivative, Liability	$ 1,000,000	[2]
Fair Value of Derivative, National amount	$ 26,000,000

[1] Derivative contracts address the effects of foreign currency exchange fluctuations for the Euro versus the U.S. dollar.

[2] We measure the fair value of our outstanding or unsettled derivatives using Level 2 fair value inputs, as we use a pricing model that takes into account the contract terms as well as current foreign currency exchange rates in active markets.