Summary of Significant Accounting Policies - Marketable Securities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Jun. 30, 2023
Marketable securities
Investment income, nonoperating	$ 6,900	$ 4,200	$ 18,100	$ 8,200
Marketable securities, short-term portion	174,900		174,900		$ 111,900
Marketable securities, long-term portion	$ 19,200		$ 19,200		$ 22,800
Marketable Securities, Maturity Date, Start	1 year		1 year		1 year
Marketable Securities, Maturity Date, End	2 years		2 years		2 years
Amortized Cost	$ 194,108		$ 194,108		$ 134,672
Allowance for Credit Losses	0		0		0
Net Carrying Amount	194,108		194,108		134,672
Gross Unrealized Gains (Losses)	(138)		(138)		(688)
Fair Value	193,970		193,970		133,984
Corporate Bonds
Marketable securities
Amortized Cost	47,548		47,548		52,567
Net Carrying Amount	47,548		47,548		52,567
Gross Unrealized Gains (Losses)	(80)		(80)		(460)
Fair Value	47,468		47,468		52,107
U.S. Treasury Notes
Marketable securities
Amortized Cost	26,679		26,679		46,156
Net Carrying Amount	26,679		26,679		46,156
Gross Unrealized Gains (Losses)	(62)		(62)		(228)
Fair Value	26,617		26,617		45,928
Commercial Paper
Marketable securities
Amortized Cost	119,881		119,881		35,949
Net Carrying Amount	119,881		119,881		35,949
Gross Unrealized Gains	4		4
Fair Value	$ 119,885		$ 119,885		$ 35,949