Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Short term investments amortized cost	$ 310,594	$ 251,959
Stockholders’ equity:
Preferred stock designated Series A, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock designated Series A, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock designated Series A, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	290,966,000	290,466,000
Common stock, shares outstanding (in shares)	244,811,000	244,315,000
Treasury stock, shares (in shares)	46,155,000	46,151,000