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v3.19.2

Borrowings - Additional Information (Details) |  | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | ---
Nov. 02, 2018 $ / shares | Mar. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) FinancingArrangement | Jan. 01, 2019 USD ($) Installment | Oct. 26, 2017 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |
Reverse stock split |  | 15-to-1 |  |  |  |
Reverse stock split ratio | 0.0667 |  |  |  |  |
Long-term debt |  | $ 13,804,000 |  |  |  |
Other Financing Arrangements |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Number of financing arrangements | FinancingArrangement |  |  |  | 3 |  |
Debt instrument, face amount |  |  |  | $ 472,000 |  |
Long-term debt |  | 184,000 | $ 238,000 |  |  |
Debt instrument, discount |  | 418,000 |  |  |  |
Other Financing Arrangement One |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument, maturity date |  |  |  | 2020-06 |  |
Other Financing Arrangement Two |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument, maturity date |  |  |  | 2020-08 |  |
Loan and Security Agreement | East West Bank |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Maximum borrowings available |  | $ 8,000,000 |  |  |  |
Line of credit facility, interest rate during period |  | 1.00% |  |  |  |
Line of credit facility, maturity date |  | 2019-05 |  |  |  |
Remaining borrowing capacity |  | $ 8,000,000 | 8,000,000 |  |  |
Subordinated Term Loan and Security Agreement | B. Riley Principal Investments, LLC |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Maximum borrowings available |  |  | 12,000,000 |  |  | $ 10,000,000
Minimum principal amount outstanding to have waiver of defined prepayment penalties |  |  | $ 10,000,000 |  |  |
Debt instrument, stated interest rate |  |  | 10.00% |  |  |
Line of credit facility, maturity date |  |  | Sep. 01, 2022 |  |  |
Outstanding borrowings |  | 12,000,000 | $ 12,000,000 |  |  |
Total accrued interest outstanding |  | 1,001,000 | 1,001,000 |  |  |
Debt instrument, convertible, price of common stock per share | $ / shares | $ 8.87 |  |  |  |  |
Subordinated Term Loan and Security Agreement | B. Riley Principal Investments, LLC | Prior to First Anniversary of Effective Date |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Designated percentage | 100.00% |  |  |  |  |
Subordinated Term Loan and Security Agreement | B. Riley Principal Investments, LLC | Year Two of Loan Agreement |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Designated percentage | 75.00% |  |  |  |  |
Subordinated Term Loan and Security Agreement | B. Riley Principal Investments, LLC | Year Three of Loan Agreement |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Designated percentage | 50.00% |  |  |  |  |
Subordinated Term Loan and Security Agreement | B. Riley Principal Investments, LLC | Year Four of Loan Agreement |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Designated percentage | 25.00% |  |  |  |  |
Subordinated Term Loan and Security Agreement | B. Riley Principal Investments, LLC | Final Year of Agreement on or Prior to Maturity Date |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Designated percentage | 12.50% |  |  |  |  |
Promissory Notes Payable |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument, outstanding balance |  | $ 619,000 | $ 718,000 |  | $ 736,000 |
Debt instrument, periodic payment, number of equal quarterly installments | Installment |  |  |  |  | 20 |
Debt instrument, frequency of periodic payment |  | quarterly |  |  |  |
Promissory Notes Payable | Minimum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument, payment term |  | 2 years |  |  |  |
Promissory Notes Payable | Maximum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument, stated interest rate |  | 8.00% |  |  |  |
Debt instrument, payment term |  | 4 years |  |  |  |

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