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Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
Income Taxes (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2018
Income Taxes [Abstract]
Income tax (benefit) expense	$ (395)	$ 0	$ (393)	$ 5
Net change in valuation allowance			36
Valuation allowance carried against net deferred tax assets	36,000		36,000			$ 36,000
ASU 2014-09 [Member]
Income Taxes [Abstract]
Deferred revenue recognized					$ 2,500
Federal [Member]
Income Taxes [Abstract]
Net operating loss carryforwards	124,000		$ 124,000
Federal [Member] \| Earliest Tax Year [Member]
Income Taxes [Abstract]
Operating loss carryforwards, expiration dates			Dec. 31, 2027
State [Member]
Income Taxes [Abstract]
Net operating loss carryforwards	$ 108,000		$ 108,000
State [Member] \| Earliest Tax Year [Member]
Income Taxes [Abstract]
Operating loss carryforwards, expiration dates			Dec. 31, 2028