Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jun. 30, 2017
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 96,711	$ 111,577
Gross Unrealized Gain	4	1
Gross Unrealized (Loss)	(40)	(70)
Fair Value	96,675	111,508
Certificate of Deposits
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	13,026	15,298
Fair Value	13,026	15,298
Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,181	10,144
Gross Unrealized Gain	4	1
Fair Value	10,185	10,145
U.S. Treasury Bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	32,108	35,086
Gross Unrealized (Loss)	(17)	(24)
Fair Value	32,091	35,062
U.S. Government Sponsored Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,876	18,357
Gross Unrealized (Loss)	(6)	(13)
Fair Value	12,870	18,344
Corporate Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	28,520	32,692
Gross Unrealized (Loss)	(17)	(33)
Fair Value	$ 28,503	$ 32,659