Fair Value Measurement of Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Fair value disclosures
Convertible notes - short term		$ 13,694	$ 13,308
Convertible notes - long-term	$ 14,189	13,866	12,947
Nonrecurring \| Carrying Value
Fair value disclosures
Loan payable	14,189	27,560	26,255
Nonrecurring \| Fair Value
Fair value disclosures
Loan payable	11,700	25,394	24,558
Nonrecurring \| Level 3 \| Carrying Value
Fair value disclosures
Convertible notes - short term		13,694	13,308
Convertible notes - long-term	14,189	13,866	12,947
Nonrecurring \| Level 3 \| Fair Value
Fair value disclosures
Convertible notes - short term		13,694	13,308
Convertible notes - long-term	$ 11,700	$ 11,700	$ 11,250
Fair value assumptions
Time to maturity (in years)	3 years 3 months 29 days
Volatility rate (as a percent)	60.00%
Risk-free interest rate (as a percent)	2.04%

Carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Convertible Notes Payable, excluding current portion. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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-Section 50
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Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

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Risk-free interest rate assumption used in valuing an instrument.

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Including the current and noncurrent portions, aggregate carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer).

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-SubTopic 210
-Section S99
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-Subparagraph (SX 210.9-03(16))
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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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