Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Jun. 30, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 52,110	$ 111,577
Gross Unrealized Gain		1
Gross Unrealized (Loss)	(64)	(70)
Fair Value	52,046	111,508
Certificate of Deposits
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,371	15,298
Fair Value	8,371	15,298
Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,368	10,144
Gross Unrealized Gain		1
Gross Unrealized (Loss)	(8)
Fair Value	10,360	10,145
U.S. Treasury Bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,109	35,086
Gross Unrealized (Loss)	(26)	(24)
Fair Value	14,083	35,062
U.S. Government Sponsored Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,882	18,357
Gross Unrealized (Loss)	(10)	(13)
Fair Value	10,872	18,344
Corporate Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,380	32,692
Gross Unrealized (Loss)	(20)	(33)
Fair Value	$ 8,360	$ 32,659