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Leases - Additional Information (Detail) $ in Thousands |  |  | 3 Months Ended |
--- | --- | --- | --- | ---
Mar. 13, 2019 USD ($) ft² m² | Aug. 31, 2017 USD ($) ft² | Mar. 31, 2019 USD ($) | Jan. 01, 2019 USD ($)
Lessee, Lease, Description [Line Items] |  |  |  |
Right-of-use assets |  |  | $ 2,705 |
Operating lease liabilities |  |  | 4,116 |
Lease liability, net of current portion |  |  | 3,275 |
Current portion of lease liability |  |  | 841 |
Accounting Standards Update 2016-02 [Member] |  |  |  |
Lessee, Lease, Description [Line Items] |  |  |  |
Right-of-use assets |  |  | 2,026 | $ 2,026
Operating lease liabilities |  |  | $ 2,538 | 2,538
Lease liability, net of current portion |  |  |  | 1,925
Current portion of lease liability |  |  |  | 613
Net deferred, accrued and prepaid rent |  |  |  | $ 512
Cambridge Lease Agreement [Member] |  |  |  |
Lessee, Lease, Description [Line Items] |  |  |  |
Lease expiration date |  | Jul. 31, 2022 |  |
Current office space under lease agreement | ft² |  | 13,000 |  |
Option to extend the lease agreement |  |  | The Company has the option to extend the lease for one period of five additional years. |
Lease, renewal term of contract |  | 5 years |  |
Base rent |  | $ 810 |  |
Waltham Lease [Member] |  |  |  |
Lessee, Lease, Description [Line Items] |  |  |  |
Current office space under lease agreement | ft² | 6,000 |  |  |
Base rent | $ 459 |  |  |
Agreement commencement date | Jan. 01, 2019 |  |  |
Operating lease expiration | 5 years |  |  |
Vienna Lease [Member] |  |  |  |
Lessee, Lease, Description [Line Items] |  |  |  |
Current office space under lease agreement | m² | 400 |  |  |
Base rent | $ 155 |  |  |
Agreement commencement date | Mar. 01, 2019 |  |  |
Lease, term of contract | 2 years |  |  |
Period for written notice for cancellable | 3 months |  |  |

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- Definition The cumulative difference between the rental payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense over the term of the leased property by the lessor or lessee, respectively. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e39896-112707 + Details
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- Definition Date which lease or group of leases is set to expire, in CCYY-MM-DD format. + References No definition available. + Details
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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. + References No definition available. + Details
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- Definition Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980 + Details
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- Definition Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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X
- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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- Definition Aggregate base rent. + References No definition available. + Details
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- Definition Agreement Commencement Date + References No definition available. + Details
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- Definition Current office space under lease agreement. + References No definition available. + Details
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- Definition Lease agreement extension description. + References No definition available. + Details
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- Definition Lease agreement period of written notice for cancellable. + References No definition available. + Details
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- Definition Operating lease expiration. + References No definition available. + Details
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- Details
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- Details
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- Details
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- Details
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