Accrued unvested common stock subject to repurchase current.

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Allowed annual percentage increase in shares authorized as percentage of outstanding shares of common stock.

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Maximum shares allowed to be issued.

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Maximum shares allowed to be issued under ESPP.

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Share based compensation arrangement by share based payment award purchase price of common stock through payroll deductions percentage.

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Share based compensation arrangement by share based payment award stock offering period.

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Unvested common shares subject to repurchase outstanding.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Aggregate number of common shares reserved for future issuance.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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The cash inflow associated with the amount received from the stock plan during the period.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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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Number of additional shares authorized for issuance under share-based payment arrangement.

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Number of shares authorized for issuance under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of shares issued during the period as a result of an employee stock purchase plan.

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Stock Incentive Plans - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 01, 2021	Mar. 31, 2018	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate proceeds from shares issued under the plan				$ 938	$ 829
Stock-based compensation				13,248	7,635
Total intrinsic value of options exercised				$ 600	$ 1,900
Weighted-average grant date fair value per share for options granted				$ 10.39	$ 12.90
Remaining shares subject to repurchase				3,091	21,666
Liability for unvested common shares subject to repurchase included in accrued expenses and other liabilities				$ 13	$ 37
Accrued Expenses and Other Liabilities \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Liability for unvested common shares subject to repurchase included in accrued expenses and other liabilities				$ 100	$ 100
2015 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option vesting period				4 years
Stock options expiration period				10 years
Number of additional shares available for future grant				0
2018 Incentive Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance		3,186,205
Allowed annual percentage increase in shares authorized as percentage of outstanding shares of common stock		4.00%
Maximum shares of common stock may be issued		20,887,347
Number of shares outstanding available for future grant				2,397,547
2018 Incentive Award Plan \| Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Allowed annual percentage increase in shares authorized as percentage of outstanding shares of common stock	4.00%
Number of additional shares added to the plan	2,010,623
2018 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for issuance		353,980
Allowed annual percentage increase in shares authorized as percentage of outstanding shares of common stock		1.00%
Number of shares outstanding available for future grant				1,039,650
Maximum shares allowed to be issued under ESPP		4,778,738
Purchase of common stock through payroll deductions expressed in percentage of fair market value			85.00%	85.00%
Common stock offering period			6 months
Number of shares issued to the plan				83,848	55,234
Aggregate proceeds from shares issued under the plan				$ 900	$ 800
Stock-based compensation				200	$ 200
2018 Employee Stock Purchase Plan \| Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Allowed annual percentage increase in shares authorized as percentage of outstanding shares of common stock	1.00%
Number of additional shares added to the plan	502,655
2015 and 2018 Stock Incentive Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense				$ 29,200
Unrecognized compensation expense estimated to be recognized over period				2 years 4 months 24 days