License, Collaboration and Service Agreements - Additional Information (Detail) $ / shares in Units, £ in Millions		1 Months Ended						3 Months Ended
	Jan. 15, 2021 USD ($)	Jun. 30, 2021 USD ($)	Nov. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2016 GBP (£)	May 31, 2016 USD ($)	Mar. 31, 2022 USD ($) $ / shares shares	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2021 USD ($) $ / shares
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of stock, value								$ 3,626,000	$ 4,123,000
Common stock, par value | $ / shares								$ 0.001					$ 0.001
Proceeds from sale of common stock to related party								$ 3,626,000	4,253,000
Revenue recognized								247,000
Deferred revenue								8,304,000					$ 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		6,600,000
License agreement research and development expense related to achievement of regulatory milestones								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
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
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								$ 0
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	$ 700,000
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
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
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								$ 5,200,000
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					$ 10,400,000
Revenue recognized								200,000
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
Proceeds from sale of common stock to related party								$ 40,000,000.0