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Commitments and Contingencies - Additional Information (Detail) - USD ($) |  |  | 3 Months Ended
--- | --- | --- | ---
Mar. 02, 2017 | Jan. 20, 2017 | Mar. 31, 2018 | Mar. 31, 2017
Loss Contingencies [Line Items] |  |  |  |
Leases expiration period |  |  | 2020 |
Rent expense under non-cancelable operating leases |  |  | $ 400,000 | $ 400,000
Royalties paid to stanford |  |  | 100,000 |
Oberland Complaint [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Settlement amount | $ (600,000) |  |  |
Conexio [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Acquisition related quarterly payments, percentage on gross revenue |  | 20.00% |  |
Periodic quarterly payments paid |  |  |  | 0
Conexio [Member] | Maximum [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Acquisition related quarterly payments on gross revenue |  | $ 700,000 |  |
Periodic quarterly payments paid |  |  | 100,000 |
Unpaid Royalties [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Royalty expenses |  |  | $ 0 | $ 300,000

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