For an unclassified balance sheet, amount of receivables arising from transactions with related parties.

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Related Party Disclosures (Details) - USD ($)	12 Months Ended
Related Party Disclosures (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Oct. 01, 2018
Debt Instrument [Line Items]
Revenue from related party	$ 225,000	$ 1,748,000	$ 0
Accounts receivable from related party	5,000	$ 140,000
Debt outstanding	302,114,000
Convertible Notes Payable \| 3.50% Convertible Senior Notes due October 1, 2024
Debt Instrument [Line Items]
Debt instrument face amount				$ 150,000,000
Interest rate				3.50%
Debt outstanding	150,000,000
Interest accrued	$ 1,313,000