INVESTMENTS (Tables)

6 Months Ended

Jun. 30, 2022

INVESTMENTS

Summary of investments in available-for-sale

									Continuous		Continuous
			Gross		Gross				Unrealized		Unrealized
			Unrealized		Unrealized				Loss Position		Loss Position
	Amortized		Holding		Holding		Fair		less than 12		greater than
June 30, 2022	Cost		Gains		Losses		Value		Months		12 Months
Available-for-sale
Short-term:
Commercial paper	$	208,909	$	—	$	—	$	208,909	$	—	$	—
Certificates of deposit		34,554		—		—		34,554		—		—
Municipal securities		212,828		78		462		212,444		462
U.S. government agency securities		74,583		—		524		74,059		524		—
U.S. treasuries		812,871		—		5,045		807,826		5,045		—
Long-term:
U.S. treasuries		56,600		24		155		56,469		155		—
Municipal securities		1,263		2		—		1,265		—
U.S. government agency securities		6,417		1		33		6,385		33		—
Total	$	1,408,025	$	105	$	6,219	$	1,401,911	$	6,219	$	—

									Continuous		Continuous
			Gross		Gross				Unrealized		Unrealized
			Unrealized		Unrealized				Loss Position		Loss Position
	Amortized		Holding		Holding		Fair		less than 12		greater than
December 31, 2021	Cost		Gains		Losses		Value		Months		12 Months
Available-for-sale
Short-term:
Commercial paper	$	334,077	$	—	$	—	$	334,077	$	—	$	—
Certificates of deposit		44,502		—		—		44,502		—		—
Municipal securities		666		—		—		666		—		—
U.S. government agency securities		62,687		—		26		62,661		26		—
U.S. treasuries		1,308,536		2		717		1,307,821		717		—
Long-term:
U.S. government agency securities		12,500		—		24		12,476		24		—
U.S. treasuries		87,133		—		190		86,943		190		—
Total	$	1,850,101	$	2	$	957	$	1,849,146	$	957	$	—

Summary of the underlying contractual maturities of investments

	June 30, 2022				December 31, 2021
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Less than 1 year:
Commercial paper	$	208,909	$	208,909	$	334,077	$	334,077
Municipal securities		212,828		212,444		666		666
U.S. government agency securities		74,583		74,059		62,687		62,661
Certificates of deposit		34,554		34,554		44,502		44,502
U.S. treasuries		812,871		807,826		1,308,536		1,307,821
Due 1 – 10 years:
Municipal securities		1,263		1,265		—		—
U.S. treasuries		56,600		56,469		87,133		86,943
U.S. government agency securities		6,417		6,385		12,500		12,476
Total	$	1,408,025	$	1,401,911	$	1,850,101	$	1,849,146