Summary of Significant Accounting Policies - Marketable Securities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Marketable securities
Investment income, nonoperating	$ 5,600	$ 2,600	$ 11,100	$ 4,000
Marketable securities, short-term portion	151,200		151,200			$ 111,900
Marketable securities, long-term portion	$ 25,400		$ 25,400			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	$ 176,621		$ 176,621			134,672
Allowance for Credit Losses	0		0		$ 0
Net Carrying Amount	176,621		176,621			134,672
Gross Unrealized Gains (Losses)	(67)		(67)			(688)
Fair Value	176,554		176,554			133,984
Corporate Bonds
Marketable securities
Amortized Cost	45,928		45,928			52,567
Net Carrying Amount	45,928		45,928			52,567
Gross Unrealized Gains (Losses)	(71)		(71)			(460)
Fair Value	45,857		45,857			52,107
U.S. Treasury Notes
Marketable securities
Amortized Cost	32,115		32,115			46,156
Net Carrying Amount	32,115		32,115			46,156
Gross Unrealized Gains (Losses)						(228)
Gross Unrealized Gains	3		3
Fair Value	32,118		32,118			45,928
Commercial Paper
Marketable securities
Amortized Cost	98,578		98,578			35,949
Net Carrying Amount	98,578		98,578			35,949
Gross Unrealized Gains	1		1
Fair Value	$ 98,579		$ 98,579			$ 35,949