Stockholders' Equity - Schedule of Changes in Stockholders Equity (Detail) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Class Of Stock [Line Items]
Beginning balance	$ 1,104,888		$ 1,235,584	$ 880,547	$ 953,754	$ 1,040,244	$ 1,235,584	$ 1,040,244
Beginning balance, shares			87,103,007				87,103,007
Exercise of stock options	4,384	$ 465		722	4,827	8,435
Exercise of stock options, shares							319,847
Issuance of shares under employee stock purchase plan		2,051			1,068
Equity-based compensation	35,352	36,400		25,215	23,068	18,491
Other comprehensive loss - unrealized loss on marketable securities	142	(1,482)		(991)	(932)	(5,128)
Other comprehensive gain (loss) from equity method investment	154	292		(805)	(560)	(302)	$ 2,240	(1,667)
Net loss	(122,224)	(123,681)		(113,229)	(100,678)	(146,872)	(349,031)	(360,779)
Ending balance	$ 1,037,414	1,104,888		824,951	880,547	953,754	$ 1,037,414	824,951
Ending balance, shares	89,097,821						89,097,821
At The Market Offerings [Member]
Class Of Stock [Line Items]
Beginning balance		1,190,843	$ 1,235,584				$ 1,235,584
Issuance of common stock	$ 14,718		1,466	31,510		38,886
Contingent consideration paid to Rewrite Holders			24,126
Exercise of stock options			755
Equity-based compensation			27,255
Other comprehensive loss - unrealized loss on marketable securities			2,989
Other comprehensive gain (loss) from equity method investment			1,794
Net loss			(103,126)
Ending balance			1,190,843
Common Stock [Member]
Class Of Stock [Line Items]
Beginning balance	$ 9	$ 9	$ 9	$ 8	$ 8	$ 7	$ 9	$ 7
Beginning balance, shares	88,347,634	88,095,779	87,103,007	76,000,745	75,624,167	74,485,883	87,103,007	74,485,883
Contingent consideration paid to Rewrite Holders			$ 567,045
Exercise of stock options, shares	241,123	30,371	48,353	33,336	315,747	503,830
Vesting of restricted stock units, shares	103,732	151,853	342,025	662	36,515	54,666
Issuance of shares under employee stock purchase plan, shares		69,631			24,316
Ending balance	$ 9	$ 9	$ 9	$ 8	$ 8	$ 8	$ 9	$ 8
Ending balance, shares	89,097,821	88,347,634	88,095,779	76,587,947	76,000,745	75,624,167	89,097,821	76,587,947
Common Stock [Member] | At The Market Offerings [Member]
Class Of Stock [Line Items]
Issuance of common stock						$ 1
Number of stock additionally invested	405,332		35,349	553,204		579,788
Additional Paid-In Capital [Member]
Class Of Stock [Line Items]
Beginning balance	$ 2,512,741	$ 2,473,825	$ 2,420,223	$ 1,840,644	$ 1,811,681	$ 1,745,870	$ 2,420,223	$ 1,745,870
Contingent consideration paid to Rewrite Holders			24,126
Exercise of stock options	4,384	465	755	722	4,827	8,435
Issuance of shares under employee stock purchase plan		2,051			1,068
Equity-based compensation	35,352	36,400	27,255	25,215	23,068	18,491
Ending balance	2,567,195	2,512,741	2,473,825	1,898,091	1,840,644	1,811,681	2,567,195	1,898,091
Additional Paid-In Capital [Member] | At The Market Offerings [Member]
Class Of Stock [Line Items]
Issuance of common stock	14,718		1,466	31,510		38,885
Accumulated Other Comprehensive Loss [Member]
Class Of Stock [Line Items]
Beginning balance	(3,868)	(2,678)	(7,461)	(9,554)	(8,062)	(2,632)	(7,461)	(2,632)
Other comprehensive loss - unrealized loss on marketable securities	142	(1,482)	2,989	991	(932)	(5,128)
Other comprehensive gain (loss) from equity method investment	154	292	1,794	(805)	(560)	(302)
Ending balance	(3,572)	(3,868)	(2,678)	(9,368)	(9,554)	(8,062)	(3,572)	(9,368)
Accumulated Deficit [Member]
Class Of Stock [Line Items]
Beginning balance	(1,403,994)	(1,280,313)	(1,177,187)	(950,551)	(849,873)	(703,001)	(1,177,187)	(703,001)
Net loss	(122,224)	(123,681)	(103,126)	(113,229)	(100,678)	(146,872)
Ending balance	$ (1,526,218)	$ (1,403,994)	$ (1,280,313)	$ (1,063,780)	$ (950,551)	$ (849,873)	$ (1,526,218)	$ (1,063,780)