Short-Term Investments - Schedule of Short-Term Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized cost	$ 123,395	$ 71,894
Short-term investments, Gross unrealized gains	590	75
Short-term investments, Gross unrealized losses	(11)
Short-term investments	123,974	71,969
U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized cost	28,281	64,683
Short-term investments, Gross unrealized gains	88	75
Short-term investments, Gross unrealized losses	(1)
Short-term investments	28,368	64,758
Corporate Bonds
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized cost	70,781	4,787
Short-term investments, Gross unrealized gains	360
Short-term investments, Gross unrealized losses	(10)
Short-term investments	71,131	4,787
Asset-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized cost	24,333	2,424
Short-term investments, Gross unrealized gains	142
Short-term investments	$ 24,475	$ 2,424