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Share based payment award options, gross grants in the period with exercise price below the market price.

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Aggregate number of common shares reserved for future issuance.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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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 cash inflow from exercise of option under share-based payment arrangement.

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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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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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Number of options outstanding, including both vested and non-vested options.

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Weighted average remaining contractual term of exercisable stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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Stockholder's Equity - Stock Options Narrative (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 11, 2011	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 25, 2019	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, shares authorized (in shares)		235,000,000	175,000,000	125,000,000		75,000,000
Shares reserved for issuance under 2019 plan (in shares)					14,000,000
Options outstanding (in shares)		7,060,966	5,496,971	4,406,004		2,712,954
Company employees, directors and affiliates stock option exercised (in shares)		1,400,003	799,800	350,441
Proceeds from common stock		$ 3,369	$ 2,321	$ 670
Weighted average grant date fair value of options granted (in usd per share)		$ 5.13	$ 4.29	$ 1.57
Number of options granted in period with exercise price below market price (in shares)		0	0	0
Unrecognized compensation cost related to non-vested share-based compensation awards granted		$ 7,900
Unrecognized compensation cost related to non-vested share-based compensation awards granted year		3 years
Employees and Directors Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Company employees, directors and affiliates stock option exercised (in shares)		1,400,000	800,000	400,000
Proceeds from common stock		$ 3,400	$ 2,300	$ 700
Intrinsic value of options exercised		$ 3,500	$ 1,900	$ 300
2011 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in shares of common stock authorized (in shares)				7,100,000
Options outstanding (in shares)		2,919,424
2011 Equity Incentive Plan \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, shares authorized (in shares)				11,050,000
2011 Equity Incentive Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, shares authorized (in shares)				18,150,000
Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining contractual life	10 years