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Term Loan Obligations - Term Loan Outstanding (Details) - Term Loan [Member] - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017 | May 29, 2015
Additional details relating term loan that is outstanding [Abstract] |  |  |  |  |  |  |
Origination Date |  | May 29, 2015 | May 29, 2015 |  | May 29, 2015 |  |
Original Loan Amount |  |  | $ 17,700 |  | $ 17,700 |  | $ 17,700
Interest Rate | [1] |  | 8.95% |  | 8.95% |  |
Current Monthly Payment |  |  | $ 100 | [2] | $ 100 | [3] |
Original Term |  |  | 48 months |  | 48 months |  |
Remaining Principal (Face Value) |  |  | $ 12,980 |  | $ 12,980 |  |
[1] | 3 month LIBOR rate with a floor of 1% plus 7.95%
[2] | Monthly payment as of December 2018, which reflects interest only
[3] | Monthly payment as of December 2017, which reflects interest only

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- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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