Fair Value Measurement

The valuation hierarchy for disclosure of assets and liabilities reported at fair value prioritizes the inputs for such valuations into three broad levels:


•	Level 1: quoted prices (unadjusted) in active markets for identical assets or liabilities;


•	Level 2: quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument; or


•	Level 3: unobservable inputs based on the Company's own assumptions used to measure assets and liabilities at fair value.

A financial asset's or liability's classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement.

The following tables provide the assets carried at fair value and measured on a recurring basis:



			Fair Value Measurements at Reporting Date Using:
(in thousands)	March 31, 2018		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents	$	324,823	$	324,823	$	—	$	—
Short-term investments	$	4,275	$	—	$	4,275	$	—
Deferred compensation plan investments	$	4,353	$	4,353	$	—	$	—



			Fair Value Measurements at Reporting Date Using:
(in thousands)	December 31, 2017		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents	$	312,914	$	312,914	$	—	$	—
Short-term investments	$	286	$	—	$	286	$	—
Deferred compensation plan investments	$	3,742	$	3,742	$	—	$	—

The cash equivalents in the preceding tables represent money market funds.

The short-term investments in the preceding tables represent deposits held by certain foreign subsidiaries of the Company. The deposits have fixed interest rates with maturity dates ranging from three months to one year.

The deferred compensation plan investments in the preceding tables represent trading securities held in a rabbi trust for the benefit of the non-affiliate independent directors. These securities consist of mutual funds traded in an active market with quoted prices. As a result, the plan assets are classified as Level 1 in the fair value hierarchy. The plan assets are recorded within other long-term assets on the Company's condensed consolidated balance sheets.

The carrying values of cash, accounts receivable, accounts payable, accrued expenses, other accrued liabilities and short-term obligations approximate their fair values because of their short-term nature.