Derivative Instruments

The notional amount of the Company's foreign currency derivatives are summarized as follows (in millions):



	As of December 31,
	2017		2016
Cash flow hedges	$	521.1	$	172.0
Non-designated derivatives	108.3		—
Total	$	629.4	$	172.0

Cash Flow Hedges

The Company uses foreign currency forward contracts to hedge the Company's planned cost of revenues and operating expenses denominated in foreign currencies. These derivatives are designated as cash flow hedges. Execution of cash flow hedge derivatives typically occurs every month with maturities of eighteen months or less. As of December 31, 2017, an estimated $7.6 million of existing gains or losses within accumulated other comprehensive loss is expected to be reclassified into earnings within the next 12 months.

The Company recognized an unrealized gain of $20.2 million and unrealized losses of $1.3 million and $6.3 million in accumulated other comprehensive loss for the effective portion of its derivative instruments during the years ended December 31, 2017, 2016, and 2015, respectively. The Company reclassified gains of $7.6 million and $1.8 million and a loss of $9.6 million out of accumulated other comprehensive loss to cost of revenues and operating expenses in the Consolidated Statement of Operations during the years ended December 31, 2017, 2016, and 2015, respectively.

The ineffective portion of the Company's derivative instruments recognized in its Consolidated Statements of Operations were not material during the years ended December 31, 2017, 2016, and 2015, respectively.

See Note 5, Fair Value Measurements, for the fair values of the Company’s derivative instruments in the Consolidated Balance Sheets.

Non-Designated Derivatives

The Company also uses foreign currency forward contracts to mitigate variability in gains and losses generated from the remeasurement of certain monetary assets and liabilities denominated in foreign currencies. These foreign exchange forward contracts typically have maturities of approximately one month. The outstanding non-designated derivative instruments are carried at fair value. Changes in the fair value of these derivatives recorded in other expense, net within the Consolidated Statements of Operations were not material during the years ended December 31, 2017, 2016, and 2015.

See Note 2, Significant Accounting Policies, for the Company’s policy regarding the offsetting of derivative assets and derivative liabilities.