Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Federal statutory income tax rate (percent)	35.00%	21.00%	28.00%
Tax at federal statutory rate (benefit)		$ (5,433)	$ (13,061)	$ 909
State income tax, net of federal benefit		517	521	168
Release of foreign valuation allowance		(2,794)
Release of US valuation allowance – Tax reform		(4,680)
Establishment of Irish valuation allowance		8,642
US valuation allowance change – deferred tax movement		(4,444)	25,302	3,246
Research and development credits		(6,598)	(7,311)	(1,355)
Foreign earnings taxed at other than U.S. rates		10,562	(1,065)	(492)
Stock based compensation		2,436	(5,901)	(573)
Goodwill amortization		834	2,004	1,795
Nondeductible officer compensation		713	1,927	470
Nondeductible meals and entertainment		517	510	391
AMT credit monetization			(155)	(155)
Deferred tax liability release - Tax reform			(2,482)
Other		(293)	(144)	(64)
Provision for income taxes		$ (21)	$ 145	$ 4,340