Derivative Instruments

The Company uses derivatives to partially offset its market exposure to fluctuations in certain foreign currencies and does not enter into derivatives for speculative or trading purposes.

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



	As of
	March 31, 2019		December 31, 2018
Cash flow hedges	$	377.0	$	497.7
Non-designated derivatives	175.6		158.7
Total	$	552.6	$	656.4

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 March 31, 2019, an estimated $2.8 million of unrealized net gain within accumulated other comprehensive loss is expected to be reclassified into earnings within the next 12 months.

The Company recognized an unrealized gain of $3.4 million and $13.4 million in accumulated other comprehensive income for the effective portion of its derivative instruments for the three months ended March 31, 2019 and March 31, 2018, respectively. The Company reclassified a loss of $1.0 million and a gain of $5.6 million out of accumulated other comprehensive income to cost of revenues and operating expenses in the Condensed Consolidated Statements of Operations during the three months ended March 31, 2019 and March 31, 2018, respectively.

See Note 4, Fair Value Measurements, for the fair values of the Company's derivative instruments in the Condensed 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 to three months. 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 Condensed Consolidated Statements of Operations were not material during the three months ended March 31, 2019 and March 31, 2018.