Business And Organization [Line Items]

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- Definition

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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- Definition

Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.

+ References

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- Definition

Number of shares issued for each share of convertible preferred stock that is converted.

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- Definition

Number of common shares issuable upon conversion for each share of preferred stock to be converted.

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- Definition

The cash inflow associated with the amount received from entity's first offering of stock to the public.

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- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

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- Definition

Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

+ References

No definition available.

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DESCRIPTION OF THE BUSINESS AND BASIS OF PRESENTATION (Details) $ / shares in Units, $ in Thousands		12 Months Ended
	Jul. 30, 2021 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	Jul. 15, 2021 shares
Business And Organization [Line Items]
Issuance of common stock in connection with the initial public offering, net of underwriting discounts and issuance costs \| $	$ 455,532	$ 426,191	$ 0
Conversion ratio	1
Common stock carrying value \| $		$ 4	$ 1
Common stock, shares outstanding (in shares)			12,794,000
Common Class A
Business And Organization [Line Items]
Common stock, shares outstanding (in shares)		16,645,000
Common Class A \| IPO
Business And Organization [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	5,872,000
Sale of stock, price per share (in usd per share) \| $ / shares	$ 102.00
Common Class A \| IPO \| Stockholders
Business And Organization [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	1,406,000
Common Class A \| IPO \| Duolingo
Business And Organization [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	4,466,000
Common Class A \| Over-Allotment Option
Business And Organization [Line Items]
Sale of stock, number of shares issued in transaction (in shares)	766,000
Common Class B
Business And Organization [Line Items]
Convertible preferred stock, shares issued upon conversion (in shares)	19,074,000
Conversion ratio	1
Common stock carrying value \| $	$ 182,609
Common stock, shares outstanding (in shares)		21,627,000
Common Class B \| Founders
Business And Organization [Line Items]
Common stock, shares outstanding (in shares)				6,930,000