Short-Term Investments - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2019
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	$ 68,095,000		$ 68,095,000		$ 71,894,000
Short-term investments realized gains or losses	0	$ 0	0	$ 0
Accrued Interest Receivable
Schedule Of Available For Sale Securities [Line Items]
Amortized cost	300,000		300,000		200,000
Fair value	$ 300,000		$ 300,000		$ 200,000