Amount recognized for the passage of time, typically for liabilities, that have been discounted to their net present values. Excludes accretion associated with asset retirement obligations.

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The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

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Debt - Schedule of Debt (Details) - USD ($) $ in Thousands			12 Months Ended
Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2015
Debt Instrument [Line Items]
Debt, gross	$ 33,714		$ 33,714
Less: discount	(79)	$ (1,087)	(79)	$ (1,087)
Accretion of interest	19	0	20	0	$ 0
Total debt, net carrying value	33,654	37,039	33,654	37,039
Less: current portion of debt	(742)	(19,712)	(742)	(19,712)
Total debt, less current portion	32,912	17,327	32,912	17,327
Notes Payable
Debt Instrument [Line Items]
Debt, gross	1,120	25,626	1,120	25,626
Total debt, net carrying value	1,041	24,539	1,041	24,539
Notes Payable \| 2014 Loan and Security Agreement
Debt Instrument [Line Items]
Debt, gross	0	20,000	0	20,000
Notes Payable \| 2013 Loan and Security Agreement
Debt Instrument [Line Items]
Debt, gross	0	2,500	0	2,500
Notes Payable \| Promissory Note to USAC
Debt Instrument [Line Items]
Debt, gross	120	1,459	120	1,459
Notes Payable \| FCC Civil Penalty
Debt Instrument [Line Items]
Debt, gross	1,000	1,667	1,000	1,667
Less: discount						$ (300)
Total debt, net carrying value	900		900
Line of Credit
Debt Instrument [Line Items]
Debt, gross	$ 32,594	$ 12,500	$ 32,594	$ 12,500