Future Minimum Payments Under Loans Payable (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
2020 (remaining 3 months)	$ 366
2021	3,961
2022	8,277
2023	7,272
Long-term Debt, Gross, Total	19,876
Less amount representing interest	(3,043)
Less unamortized discount	(1,383)	$ (400)
Less deferred charges	(1,833)
Less loans payable current, net of discount		(9,569)
Loans payable, net of current portion and discount	$ 13,617	$ 6,197

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Amount, after accumulated amortization, of debt discount.

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