Commitments and Contingencies - Schedule of Other Information related to Stamford Lease (Detail) - Stamford Operating Lease [Member] $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Other Commitments [Line Items]
Operating cash outflows relating to operating lease	$ (306)	$ (909)
ROU assets obtained in exchange for new operating lease liabilities		$ 3,636
Remaining lease term-operating lease (years)	4 years 2 months 12 days	4 years 2 months 12 days
Discount rate - operating lease	7.00%	7.00%

Discount rate used by lessee to determine present value of operating lease payments.

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Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB
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Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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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.

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No definition available.

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- Definition

Amount of increase in right-of-use asset obtained in exchange for operating lease liability.

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-Publisher FASB
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