Investments (Tables)

6 Months Ended

Jun. 30, 2021

Investments

Schedule of gross unrealized gains and losses, and the amortized cost, allowance for credit losses, and fair value of those investments classified as available-for-sale

The amortized cost, gross unrealized gains and losses, fair value of those investments classified as available-for-sale, and allowance for credit losses at June 30, 2021 are summarized as follows (in thousands):

	Amortized		Gross		Gross		Fair		Allowance for
	Cost		Unrealized Gains		Unrealized Losses		Value		Credit Losses
Corporate bonds	$	707,022	$	51	$	(1,989)	$	705,084		—
Commercial paper		329,471		253		(2)		329,722		—
Certificates of deposit		27,460		—		(6)		27,454		—
U.S. Treasuries		170,672		—		(195)		170,477		—
Municipal debt		9,993		—		(9)		9,984		—
Total	$	1,244,618	$	304	$	(2,201)	$	1,242,721	$	—

Schedule of investments classified as equity securities

The cost, gross unrealized gains and losses, and fair value of those investments classified as equity securities at June 30, 2021 are summarized as follows (in thousands):

	June 30, 2021
			Gross		Gross		Fair
		Cost	Unrealized Gains		Unrealized Losses		Value
Fixed income mutual funds	$	89,962	$	17	$	(81)	$	89,898
Exchange traded mutual funds		30,016		388		—		30,404
Total	$	119,978	$	405	$	(81)	$	120,302

Schedule of the amortized cost and fair value of investments classified as available-for-sale, by contractual maturity

A summary of the amortized cost and fair value of investments classified as available-for-sale, by contractual maturity, as of June 30, 2021 is as follows (in thousands):

	June 30, 2021
		Amortized	Fair
Maturity:		Cost	Value
Within one year	$	717,531	$	717,285
After one through five years		527,087		525,436
Total	$	1,244,618	$	1,242,721