Sutro Biopharma, Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Collaboration and License Agreements and Supply Agreements - Additional Information (Details)

Collaboration and License Agreements and Supply Agreements - Additional Information (Details)		1 Months Ended									3 Months Ended
	Oct. 01, 2018 USD ($) $ / shares shares	Dec. 31, 2018 USD ($)	Aug. 31, 2018 USD ($)	Jul. 31, 2018 Program	Sep. 30, 2017 USD ($)	Aug. 31, 2017 USD ($) Program	Jun. 30, 2016 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)	May 31, 2014 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Jan. 01, 2019 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Receivable from agreement		$ 2,489,000									$ 3,338,000
Accounts receivable, net		2,489,000
Accounts receivable, related parties		959,000									1,188,000
Contingent payments of embedded derivative and related liability		100,000									100,000
EMD Serono
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognition of up front payment											20,000,000
Changes in deferred revenue											$ 600,000
The Leukemia & Lymphoma Society, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research development and commercialization agreement termination period											12 years
Research development and commercialization agreement termination description											The LLS Agreement terminates upon the earlier of (a) fulfillment of all payment obligations by both parties or (b) 12 years after the effective date. LLS may terminate the LLS Agreement at any time with 60 days’ prior written notice. Either the Company or LLS has the right to terminate the LLS Agreement based on the other party’s uncured material breach.
SutroVax
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Receivable from agreement		49,000									$ 300,000
Accounting Standards Update 2014-09
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable, net													$ 2,489,000
Celgene Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront, nonrefundable payment received									$ 83,100,000
Contingent payment received								$ 15,000,000
Milestone payment received							$ 25,000,000
Additional milestone payment received							$ 10,000,000
Number of programs advancing through preclinical development \| Program						4
Option fee payment received						$ 12,500,000
Milestone revenue recognized		10,000			$ 10,000
Deferred revenue		11,400,000				8,200,000					5,900,000
Revenue, remaining performance obligation, amount						20,700,000
Celgene Agreement \| Accounting Standards Update 2014-09 \| Difference between Revenue Guidance in Effect before and after Topic 606
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue													(4,500,000)
Total revenue											1,100,000
Celgene Agreement \| First Performance Obligation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue, remaining performance obligation, amount						8,200,000
Celgene Agreement \| Future Services on Collaboration Joint Steering Committee ("JSC")
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue, remaining performance obligation, amount						200,000
Celgene Agreement \| Third Performance Obligation
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue, remaining performance obligation, amount						$ 12,300,000
2018 Celgene Master Services Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Other revenue-related parties											500,000	$ 1,900,000
2018 Merck Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue		53,000,000									43,700,000
Receivable from agreement		900,000									900,000
2018 Merck Agreement \| Merck Sharp & Dohme Corp
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of research programs \| Program				3
Upfront payment received			$ 60,000,000
Recognition of up front payment			47,100,000
Revenue performance obligation amounts recognized in revenues			700,000
Extension option fee associated with contingent program			4,900,000
Embedded interest associated with upfront payment											900,000
FTE Funding Received											800,000
Revenue recognition aggregate milestone payments eligible to receive											$ 1,600,000,000
Milestone method revenue recognition description											If one or more products from each of the target programs are developed for non-oncology or a single indication, the Company will be eligible for reduced aggregate milestone payments. In addition, the Company is eligible to receive tiered royalties ranging from mid-single digit to low teen percentages on the worldwide sales of any commercial products that may result from the collaboration.
2018 Merck Agreement \| Merck Sharp & Dohme Corp \| Common Stock \| Private Placement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Stock Issued, shares \| shares	666,666
Share issue price per share \| $ / shares	$ 15.00
Proceeds from issuance of common stock	$ 10,000,000
2018 Merck Agreement \| Merck Sharp & Dohme Corp \| Series E Redeemable Convertible Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Stock Issued, shares \| shares	74,794,315
Share issue price per share \| $ / shares	$ 0.2674
Proceeds from issuance of redeemable convertible preferred stock gross	$ 20,000,000
2018 Merck Agreement \| Merck Sharp & Dohme Corp \| Collaboration Revenue, Amortization of Up-front Payment
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue											$ 3,000,000
2018 Merck Agreement \| Accounting Standards Update 2014-09 \| Celgene
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Changes in deferred revenue due to adoption of new accounting policy													$ 6,300,000
2018 Merck Agreement \| Accounting Standards Update 2014-09 \| Merck Sharp & Dohme Corp
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total interest of unearned revenue											7,600,000
Collaboration Agreement \| EMD Serono
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Up-front, nonrefundable and non-creditable payment received										$ 10,000,000
MDA Agreement \| EMD Serono
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue		1,700,000									900,000
Up-front, nonrefundable and non-creditable payment received									$ 10,000,000
Maximum amount eligible to receive for each product developed											52,500,000
Accounts receivable, net		900,000									1,500,000
Supply Agreement \| SutroVax
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Other revenue-related parties											300,000
Accounts receivable, related parties		$ 49,000									300,000
Research Development and Commercialization Agreement \| The Leukemia & Lymphoma Society, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone payment received											1,000,000
Maximum contribution in clinical development			6,000,000								6,000,000
Initial milestone payment			$ 500,000
Maximum aggregate payment											$ 19,500,000