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Long Term Debt - FFG Loan Agreement - Additional Information (Detail) - USD ($) $ in Thousands |  | 3 Months Ended |
--- | --- | --- | ---
Mar. 08, 2019 | Mar. 31, 2019 | Dec. 31, 2018
Schedule Of Long Term Debt [Line Items] |  |  |
Debt instrument, outstanding value |  | $ 19,546 | $ 10,000
Debt instrument, current portion |  | $ 5,298 | $ 1,687
FFG Loan Agreement [Member] |  |  |
Schedule Of Long Term Debt [Line Items] |  |  |
Debt instrument, maturity start date |  | Mar. 31, 2019 |
Debt instrument, maturity end date |  | Mar. 31, 2021 |
Debt instrument, outstanding value |  | $ 9,546 |
Debt instrument, current portion |  | $ 2,914 |
Number of years accelerated payment | 3 years | 5 years |
Repayment of outstanding loan principal |  | $ 2,914 |
Percentage of minimum cash balance | 70.00% |  |
FFG Loan Agreement [Member] | Minimum [Member] |  |  |
Schedule Of Long Term Debt [Line Items] |  |  |
Debt instrument, interest rate |  | 0.75% |
FFG Loan Agreement [Member] | Maximum [Member] |  |  |
Schedule Of Long Term Debt [Line Items] |  |  |
Debt instrument, interest rate |  | 2.00% |

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- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + 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)(3) -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(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: 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 Reference 4: 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 + Details
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