Fair Value Measurements

3 Months Ended

Mar. 31, 2020

Fair Value, Measurement Inputs, Disclosure

Fair Value Measurements

The Company utilizes the market approach to measure the fair value of its financial assets. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets. The assets classified as Level 2 primarily utilize quoted market prices or alternative pricing sources including transactions involving identical or comparable assets and models utilizing market observable inputs for valuation of these securities. No changes in valuation techniques or inputs occurred during the three months ended March 31, 2020.

Financial instruments measured at fair value on a recurring basis:



	March 31, 2020						December 31, 2019
(in thousands)	Total		Level 1		Level 2		Total		Level 1		Level 2
Cash equivalents
Money market funds	$	47,774	$	47,774	$	—	$	42,653	$	42,653	$	—
Commercial paper	7,135		—		7,135		5,807		—		5,807
Municipal debt securities	4,547		—		4,547		1,202		—		1,202
Total cash equivalents	59,456		47,774		11,682		49,662		42,653		7,009
Short-term
Corporate debt securities	158,060		—		158,060		145,975		—		145,975
Commercial paper	142,667		—		142,667		161,286		—		161,286
Municipal debt securities	8,678		—		8,678		12,237		—		12,237
US Treasury bonds	3,076		—		3,076		2,915		—		2,915
Federal agency debt securities	2,465		—		2,465		13,515		—		13,515
Total short-term	314,946		—		314,946		335,928		—		335,928
Long-term
Federal agency debt securities	11,019		—		11,019		—		—		—
Corporate debt securities	—		—		—		15,396		—		15,396
US Treasury bonds	—		—		—		146		—		146
Total long-term	11,019		—		11,019		15,542		—		15,542
Total financial instruments	$	385,421	$	47,774	$	337,647	$	401,132	$	42,653	$	358,479

None of the Company's debt is publicly held and as a result, the Company has determined the estimated fair value of these notes to be Level 3. Certain inputs used to determine fair value are unobservable and, therefore, could be sensitive to changes in inputs. The Company utilizes the discounted cash flow method to estimate the fair value of Level 3 debt.

Carrying value and estimated fair value of long-term debt, including current maturities and without reduction for related costs, are as follows:



	March 31, 2020				December 31, 2019
(in thousands)	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value		Hierarchy Level
Non-publicly held debt	$	1,397,339	$	1,235,274	$	1,329,882	$	1,140,232	3

Due to their short-term nature, the carrying amounts of cash, cash equivalents, restricted cash, accounts receivable and accounts payable approximate fair value.