Fair Value Measurements Fair Value Measurements (Notes)

3 Months Ended

Mar. 31, 2019

Fair Value Disclosures [Abstract]

Fair Value Disclosures [Text Block]

4. Fair Value Measurements

We account for our financial assets in accordance with Accounting Standard Codification 820, Fair Value Measurement. This standard defines fair value, establishes a framework for measuring fair value and expands disclosures about fair value measurements. The fair value measurement disclosures are grouped into three levels based on valuation factors:

• Level 1 - quoted prices in active markets using identical assets

• Level 2 - significant other observable inputs, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other observable inputs

• Level 3 - significant unobservable inputs

Fair Value of Instruments Measured and Recognized at Fair Value

The following table summarizes the levels of fair value measurements of our financial assets:

	March 31, 2019						December 31, 2018
(in thousands)	Total		Level 1		Level 2		Total		Level 1		Level 2
Money market funds	$	377,377	$	377,377	$	—	$	325,819	$	325,819	$	—
U.S. Treasury bills	62,272		62,272		—		52,197		52,197		—
Municipal bonds	4,567		—		4,567		10,634		—		10,634
Total	$	444,216	$	439,649	$	4,567	$	388,650	$	378,016	$	10,634

The municipal bond securities valued as Level 2 are primarily pre-refunded municipal bonds that are secured by escrow funds containing U.S. government securities. Our valuation techniques used to measure fair value for these securities during the period consisted primarily of third-party pricing services that utilized actual market data such as trades of comparable bond issues, broker/dealer quotations for the same or similar investments in active markets and other observable inputs.

The following is a summary of our available-for-sale marketable securities:

(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
March 31, 2019
U.S. Treasury bills	$	49,028	$	8	$	(4	)	$	49,032
Municipal bonds	4,567		—		—			4,567
Total	$	53,595	$	8	$	(4	)	$	53,599
December 31, 2018
U.S. Treasury bills	$	50,150	$	—	$	(3	)	$	50,147
Municipal bonds	10,640		1		(7		)	10,634
Total	$	60,790	$	1	$	(10	)	$	60,781

As of March 31, 2019, the contractual maturities of our marketable securities were as follows:

(in thousands)	Amortized Cost		Estimated Fair Value
Less than one year	$	53,595	$	53,599
One to five years	—		—
Total	$	53,595	$	53,599

Fair Value of Other Financial Instruments

The carrying amounts of cash, cash equivalents, restricted cash, accounts receivable, deposits and accounts payable approximate their fair values due to the short-term maturities of these instruments.

As of March 31, 2019, the carrying value of borrowings under our revolving credit facility approximates fair value and was classified as Level 2 in the fair value hierarchy. Please read Note 5, “Long-Term Debt,” for additional information.