Basis of Presentation and Summary of Significant Accounting Policies - Additional information (Detail) - USD ($)			1 Months Ended	3 Months Ended		6 Months Ended
	Aug. 02, 2022	Jul. 01, 2021	Nov. 30, 2020	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Accounting Policy [Line Items]
Cash and cash equivalents				$ 104,315,000		$ 104,315,000		$ 325,007,000
Marketable securities				96,400,000		96,400,000
Accumulated deficit				(1,576,399,000)		(1,576,399,000)		(1,408,383,000)
Newly issued shares, value					$ 406,869,000
Revenue recognized				2,700,000		4,900,000
Contract liabilities				12,700,000		12,700,000		$ 10,400,000
Other income, net				0	0	400,000	$ 0
Unsatisfied performance obligations				30,700,000		30,700,000
Loss on extinguishment of convertible notes				0	(0)	0	(131,908,000)
Research and development				$ 40,798,000	$ 10,458,000	$ 78,725,000	22,435,000
Common Class A [Member]
Accounting Policy [Line Items]
Common stock, par value				$ 0.0001		$ 0.0001		$ 0.0001
Common stock Value				$ 22,000		$ 22,000		$ 22,000
B. Riley Principal Capital II, LLC [Member] | Common Class A [Member] | Maximum [Member] | Subsequent Event [Member]
Accounting Policy [Line Items]
Newly issued shares, value	$ 100,000,000
Number of shares, percentage	19.99%
Apollo Fusion Inc [Member]
Accounting Policy [Line Items]
Total purchase consideration, net of cash acquired		$ 70,768,000
October 2019 Convertible Notes [Member]
Accounting Policy [Line Items]
Loss on extinguishment of convertible notes			$ 600,000				$ (133,800,000)
Exchange of Stock for Stock [Member]
Accounting Policy [Line Items]
Common stock, par value				$ 0.0001		$ 0.0001