License, Collaboration and Service Agreements - Additional Information (Detail) $ / shares in Units, £ in Millions		1 Months Ended						3 Months Ended					6 Months Ended
	Jan. 15, 2021 USD ($)	Jun. 30, 2021 USD ($)	Nov. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2016 GBP (£)	May 31, 2016 USD ($)	Jun. 30, 2022 USD ($) $ / shares	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) $ / shares
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of stock, value								$ 577,000					$ 4,203,000	$ 4,123,000
Common stock, par value | $ / shares								$ 0.001					$ 0.001		$ 0.001
Proceeds from sale of common stock to related party													$ 4,203,000	4,253,000
Revenue recognized								$ 896,000	$ 2,106,000				1,143,000	2,106,000
Deferred revenue								7,886,000					7,886,000		$ 8,786,000
Cantab Related Agreements [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential milestone payment upon achievement of specified commercial milestone						£ 5.0							6,100,000
License agreement research and development expense related to achievement of regulatory milestones								0	0				0	0
Potential milestone payment upon achievement of specified clinical, regulatory and commercial milestones					$ 5,800,000
Vertex License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement research and development expense related to achievement of regulatory milestones								0	0				$ 0	0
Contract termination period													10 years
Nonrefundable upfront payments							$ 500,000
Potential milestone payment upon achievement of specified clinical, regulatory and commercial milestones							$ 80,200,000
Contract termination period if no material development or commercialization occurs													1 year
Meiji License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Nonrefundable upfront payments				$ 600,000
Sublicense fee payable to counter party								7,500,000					$ 7,500,000
Potential milestone payments upon achievement of specified condition				$ 1,000,000.0
License agreement fixed assets related payments												$ 1,600,000
Potential milestone payments upon completion and delivery of results of a clinical study													1,000,000.0
Future milestone payments													$ 1,000,000.0
Everest License Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Period of option granted on an agreement													12 months
Upfront payment received											$ 3,000.0
Potential milestone payments upon completion and delivery of results of a clinical study										$ 2,000,000.0
Revenue recognized								800,000	800,000				$ 800,000	800,000
Everest License Agreement [Member] | SPR 206 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received		$ 800,000									2,000,000.0
Potential milestone payments upon completion and delivery of results of a clinical study	$ 1,500,000	$ 800,000
Milestones payment received	$ 1,300,000
Everest License Agreement [Member] | SPR 741 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received											$ 1,000,000.0
Everest License Agreement [Member] | Maximum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement termination period upon written notice	180 days
Everest License Agreement [Member] | Maximum [Member] | SPR 206 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Receivable amount upon achievement of certain milestone	$ 38,000,000.0							59,500,000					59,500,000
Everest License Agreement [Member] | Minimum [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Agreement termination period upon written notice	90 days
Gates MRI [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Reduction to research and development expense								0	600,000				0	1,100,000
Savior Service Agreement [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Supervision fee amortization service period			34 months
Savior Service Agreement [Member] | Prepaid Asset [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Non-refundable supervision fee related to commercial manufacturing facility			$ 2,000,000.0
Savior Service Agreement [Member] | Long-term Asset [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Service agreement additional payment related to facility build out costs													$ 5,300,000
Pfizer License and Share Purchase Agreements [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of stock, shares | shares													2,362,348
Issuance of stock, value													$ 27,500,000
Remaining transaction price allocated to the performance obligations								12,500,000					12,500,000
Revenue recognized								100,000	$ 1,400,000				400,000	$ 1,400,000
Deferred revenue								$ 10,300,000					10,300,000
Premium associated freestanding equity													12,500,000
Pfizer License and Share Purchase Agreements [Member] | SPR 206 [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Receivable amount upon achievement of certain milestone													$ 80,000,000.0
Issuance of stock, shares | shares													2,362,348
Share price | $ / shares								$ 16.93					$ 16.93
Proceeds from sale of common stock to related party													$ 40,000,000.0