Summary of Significant Accounting Policies - Additional Information (Details) - BFLY Operations Inc		12 Months Ended
Feb. 12, 2021 USD ($)	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)
Gross proceeds from business combination	$ 589,000,000
Number of Operating Segments \| segment		1
Deferred offering costs		$ 3,711,000	$ 0
Impairments			0
Advertising expense		$ 4,700,000	$ 900,000
Vesting period of stock options		4 years
Term of stock options		10 years

The amount of proceeds from business combination.

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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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Amount of deferred cost, excluding capitalized cost related to contract with customer; classified as noncurrent.

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The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

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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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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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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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