Financial Instruments and Fair Value Measurements - Fair Value and Notional Principal Amounts of Outstanding or Unsettled Derivative Instruments (Details)	Dec. 31, 2016 USD ($)
Not Designated as Hedging Instrument | Foreign Exchange-forward Contracts
Derivatives Fair Value [Line Items]
Foreign currency exchange-forward contracts	$ 6,000,000	[1],[2]

[1] Derivative contracts address foreign currency exchange fluctuations for the Euro versus the U.S. dollar. The Company had no outstanding derivative contracts as of December 31, 2017 and two outstanding derivative contracts as of December 31, 2016.

[2] The fair value of our outstanding derivatives as of December 31, 2016 was not material and was reported as an asset in prepaid expenses and other current assets on our consolidated balance sheet. 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.