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Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2019 | Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract] |  |
Minimum term of non-cancellable operating leases | 1 year |
Expiration of non-cancellable operating leases maximum year | 2030 |
Operating lease cost | $ 0.5 | $ 0.3
Operating lease not yet commenced | the Company had no leases that have not yet commenced. |

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- Definition Latest period of expiration of non-cancelable operating lease. + References No definition available. + Details
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- Definition Minimum term of non-cancelable operating lease. + References No definition available. + Details
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- Definition Description of lessor's operating lease that has not yet commenced. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919359-209981 + Details
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- Definition Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980 + Details
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