License, Collaboration and Other Agreements - Additional Information (Detail) - USD ($)	1 Months Ended				3 Months Ended		12 Months Ended
	Jan. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jan. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront payment received				$ 8,000,000
Milestone payments received	$ 2,000,000
Hong Kong University of Science and Technology [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Collaborative Agreement Funding Received			$ 750,000
Funding Of Project Cost Description			The grant will fund approximately 50% of the total estimated project cost, with aTyr contributing the remaining 50%. The research grant agreement between Pangu BioPharma, HKUST and the Government of the Hong Kong Special Administration Region became effective April 1, 2020
Expenses					$ 200,000	$ 0
Development Regulatory And Sales Milestones [Member] | Kyorin Pharmaceutical Co Ltd [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Remaining receivable based on achievement of research milestones				165,000,000
Research Collaboration and Option Agreement [Member] | Kyorin Pharmaceutical Co Ltd [Member] | Collaboration Revenue [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Milestone payments received	$ 2,000,000
Stand-alone selling price of license		$ 100,000		$ 7,900,000
License and collaboration agreement revenue						8,000,000	$ 2,000,000
Research Collaboration and Option Agreement [Member] | CSL Behring [Member] | Collaboration Revenue [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront payment received					$ 0	$ 7,900,000