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Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

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The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Specific incremental costs directly attributable to a proposed or actual offering of securities which are deferred at the end of the reporting period.

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Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of discretionary contributions made by an employer to a defined contribution plan.

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Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

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Percentage employer matches of the employee's percentage contribution matched.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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Per share or per unit amount of equity securities issued.

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Significant Accounting Policies - Additional Information (Detail) ₩ / shares in Units, $ / shares in Units, ₩ in Billions		1 Months Ended	3 Months Ended	12 Months Ended
	May 15, 2020 shares	May 31, 2017 USD ($) $ / shares shares	Mar. 31, 2021 Segment	Dec. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	May 31, 2017 KRW (₩) ₩ / shares
Summary Of Significant Accounting Policies [Line Items]
Impairment of indefinite-lived intangible assets				$ 0
Impairment of goodwill				0
Defined benefit plan, benefit obligation				2,792,000	$ 1,882,000	$ 1,245,000
Defined contribution expense				467,000	394,000
Deferred offering costs					1,300,000
Advertising Expense				$ 61,800,000	28,500,000
Number of operating segments \| Segment			1	1
2.5% Convertible bonds due 2024 [Member]
Summary Of Significant Accounting Policies [Line Items]
Debt instrument face amount		$ 193,000,000					₩ 210
Debt instrument, interest rate, stated percentage		2.50%					2.50%
Debt conversion shares issued \| shares	715,258
2.5% Non convertible bonds due 2024 [Member]
Summary Of Significant Accounting Policies [Line Items]
Debt instrument face amount		$ 83,000,000					₩ 90
Debt instrument, interest rate, stated percentage		2.50%					2.50%
Debt conversion shares issued \| shares	306,539	306,540
Debt conversion shares issued price per share \| (per share)		$ 270					₩ 293,600
Other net [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred offering costs				$ 5,400,000
Employee contributions percentage one [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined contribution plan matching contribution percent				1.00%
Employee contributions percentage two [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined contribution plan matching contribution percent				5.00%
On the one percentage of employee contributions [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined contribution plan matching contribution percent of match				100.00%
On the next five percentage of employee contributions [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined contribution plan matching contribution percent of match				50.00%
Other non-current liabilities [Member]
Summary Of Significant Accounting Policies [Line Items]
Defined benefit plan, benefit obligation				$ 2,800,000	$ 1,900,000