Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2019	Mar. 31, 2020	Jun. 30, 2020	Apr. 01, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Recognition of total right-of-use assets			$ 44,209
Total operating lease liabilities			48,682
Cumulative effects adjustment for ASU 2016-02 adoption		$ 961,497	988,577
Derecognized deferred rent	$ (3,300)
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Recognition of total right-of-use assets		50,600
Total operating lease liabilities		50,700
Derecognized deferred rent		3,300
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effects adjustment for ASU 2016-02 adoption		306
Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effects adjustment for ASU 2016-02 adoption		(594,026)	$ (580,855)
Accumulated Deficit | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effects adjustment for ASU 2016-02 adoption		$ 306		$ 300