Net Loss Per Share - Summary of Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Legacy Rocket Lab preferred stock warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Equity shares		1,123,959
Legacy Rocket Lab common stock warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Equity shares		585,399
Stock Options And Restricted Stock Units [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Equity shares	34,292,250	22,088,726
Public and Private Warrants [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Equity shares	16,264,516
Legacy Rocket Lab preferred stock [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Equity shares		283,843,764