Summary of Significant Accounting Policies - Additional Information (Details) $ / shares in Units, $ in Thousands			1 Months Ended		3 Months Ended		12 Months Ended
	Feb. 28, 2022 USD ($)	Aug. 31, 2021 USD ($)	Jul. 31, 2021 USD ($) $ / shares shares	Feb. 28, 2021 USD ($) $ / shares shares	Sep. 30, 2023 Employee	Sep. 30, 2020 Employee	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Jan. 31, 2022 USD ($)	Dec. 31, 2021	Aug. 03, 2021 USD ($)	Jul. 15, 2021 USD ($)	May 31, 2020 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Net loss							$ (21,917)	$ (18,227)
Accumulated deficit							(344,251)	(322,334)
Cash, cash equivalents and restricted cash							$ 11,363
Restructuring reducation plan description							The 2023 Restructuring Plan resulted in the reduction of the Company's global employees by approximately 64 full-time employees during the second half of 2023, reducing its total headcount by approximately 37% from 172 as of June 30, 2023 to 108 as of December 31, 2023.
Repayment of loan	$ 200
Aggregate gross sales price													$ 22,800	$ 40,000
Common stock sold under agreement | shares | shares				1,186,000					2,726,000	658,000
Offering costs				$ 157				95	$ 463	$ 210
Weighted average sales price (in dollars per share) | $ / shares				$ 2.68					$ 2.92	$ 2.82
Net proceeds from common stock sold				$ 3,025				1,333	$ 7,500	$ 1,643
Allowance for potential customer revenue credits							$ 12	110
Unrealized gains (losses) on money market funds							0	0
Payments to develop software							1,906	1,853
Amortization of capitalized costs							1,701	1,810
Unamortized internally developed software costs, including construction in progress							3,276	3,071
Uncertain tax position							0	0
Impairment loss on long-lived assets							3,276	0
Advertising and promotion expense							909	653
Contributions by employer							65	69
Aggregate foreign currency (losses) gains							$ (137)	(127)
At-the-market Offering [Member]
Summary Of Significant Accounting Policies [Line Items]
Aggregate gross sales price													50,000
Accounting Standards Update 2019-12 [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounting standards update, adopted [true false]												true
Accounting standards update, immaterial effect [true false]												true
Software and Software Development Costs [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life							3 years
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents, fair value disclosure							$ 10,548	$ 26,645
Google [Member] | Accounts Receivable [Member] | Customer Concentration Risk [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration risk							46.00%	40.00%
Google [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration risk							40.00%	36.00%
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Aggregate gross sales price		$ 50,000					$ 50,000						100,000
Offering costs		$ 100,000
Paycheck Protection Program [Member]
Summary Of Significant Accounting Policies [Line Items]
Aggregate principal amount of the loan											$ 3,117
Paycheck Protection Program [Member] | Harvest Small Business Finance, LLC [Member]
Summary Of Significant Accounting Policies [Line Items]
Aggregate principal amount of the loan															$ 3,320
Restructuring and Reduction in Force Plan [Member] | 2020 Restructuring Plan [Member]
Summary Of Significant Accounting Policies [Line Items]
Expected reduction of workforce | Employee					64	60
United Kingdom [Member]
Summary Of Significant Accounting Policies [Line Items]
Contributions by employer							$ 242	$ 91
2021 Equity Distribution Agreement [Member]
Summary Of Significant Accounting Policies [Line Items]
Common stock sold under agreement | shares | shares			4,316,000
Weighted average sales price (in dollars per share) | $ / shares			$ 9.27
Net proceeds from common stock sold			$ 38,800
2021 Equity Distribution Agreement [Member] | JMP Securities [Member]
Summary Of Significant Accounting Policies [Line Items]
Aggregate gross sales price													$ 50,000
Common stock sold under agreement | shares | shares								1,100,000
Offering costs								$ 100
Weighted average sales price (in dollars per share) | $ / shares								$ 1.33
Net proceeds from common stock sold								$ 1,300
Net of securities fees			$ 1,200
2021 Equity Distribution Agreement [Member] | JMP Securities [Member] | Maximum [Member] | At-the-market Offering [Member]
Summary Of Significant Accounting Policies [Line Items]
Aggregate gross sales price														$ 40,000