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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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		6 Months Ended
	Jan. 01, 2021	Mar. 31, 2018	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate proceeds from shares issued under the plan					$ 446	$ 537
Stock-based compensation			$ 4,473	$ 3,452	8,356	6,336
Total intrinsic value of options exercised					$ 600	$ 500
Weighted-average grant date fair value per share for options granted					$ 7.77	$ 11.22
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		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%	4.00%
Maximum shares of common stock may be issued		20,887,347
Number of additional shares added to the plan	2,010,623
Number of shares outstanding available for future grant			2,390,494		2,390,494
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%	1.00%
Number of additional shares added to the plan	502,655
Number of shares outstanding available for future grant			1,493,513		1,493,513
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%
Common stock offering period				6 months
Number of shares issued to the plan					48,792	39,471
Aggregate proceeds from shares issued under the plan					$ 400	$ 500
Stock-based compensation			$ 100	$ 100	100	$ 100
2015 and 2018 Stock Incentive Plans
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense			$ 38,400		$ 38,400
Unrecognized compensation expense estimated to be recognized over period					2 years 7 months 6 days