Merger - Summary of Shares of Common Stock Issued and Outstanding in Business Combination (Parenthetical) (Details) - shares	Sep. 30, 2021	Dec. 31, 2020
Subsidiary, Sale of Stock [Line Items]
Number of options outstanding	9,682,869	10,215,834
Common stock, shares outstanding (in shares)	112,818,724	22,118,619
Old Owlet [Member]
Subsidiary, Sale of Stock [Line Items]
Number of options outstanding	3,150,463
Common stock, shares outstanding (in shares)	2,807,500