Debt - Additional Information (Detail) $ in Thousands		9 Months Ended
	Mar. 20, 2019 USD ($)	Sep. 30, 2019 USD ($) Tranche
Debt Instrument [Line Items]
Loan amount		$ 30,000
Number of tranches in loan agreement | Tranche		4
2016 Loan Agreement [Member]
Debt Instrument [Line Items]
Loan amount		$ 11,800
Annual interest rate		7.60%
Percentage of original principal amount as final payment		5.00%
Loan Agreement [Member]
Debt Instrument [Line Items]
Loan amount		$ 30,000
Term loan principal amount	$ 40,000
Debt instrument, interest rate terms	The term loan bears interest at an annual rate equal to the greater of 8.55% and the prime rate of interest plus 2.55%.
Frequency of periodic payment	The Loan Agreement provides for interest-only payments until April 30, 2021, and repayment of the aggregate outstanding principal balance of the term loan in monthly installments starting on May 1, 2021 and continuing through April 1, 2023 (the “Maturity Date”).
Loan Agreement maturity date	Apr. 01, 2023
Debt instrument, fee description	The Company paid a fee of $0.3 million upon closing and is required to pay a fee of 6.35% of the aggregate amount of advances under the Loan Agreement at maturity.
Debt instrument closing fee	$ 300
Debt instrument, redemption, description	At its option, the Company may elect to prepay all or a portion of the outstanding advances by paying the entire principal balance (or a portion thereof) and all accrued and unpaid interest thereon plus a prepayment charge equal to the following percentage of the principal amount being prepaid: 2% if an advance is prepaid during the first 12 months following the applicable advance date, 1% if an advance is prepaid after 12 months but prior to 24 months following the applicable advance date, and 0.5% if an advance is prepaid any time after 24 months following the applicable advance date but prior to the Maturity Date.