Sutro Biopharma, Inc. Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Collaboration and License Agreements - Additional Information (Details)

Collaboration and License Agreements - Additional Information (Details)		1 Months Ended								3 Months Ended									12 Months Ended
	Oct. 01, 2018 USD ($) $ / shares shares	Dec. 31, 2018 USD ($)	Aug. 31, 2018 USD ($) Program	Jul. 31, 2018 Program	Aug. 31, 2017 USD ($) Program	Jun. 30, 2016 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)	May 31, 2014 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jul. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable		$ 2,489,000								$ 2,489,000					$ 1,624,000				$ 2,489,000	$ 1,624,000
Total revenue										19,086,000	$ 7,836,000		$ 5,704,000	$ 5,793,000	4,040,000	$ 17,499,000	$ 15,357,000	$ 14,845,000	38,419,000	51,741,000	$ 59,731,000
Proceeds from issuances of redeemable convertible preferred stock, net of issuance costs																			84,739,000	0	$ 0
Contingent payments of embedded derivative and related liability		100,000								100,000									$ 100,000
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
Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock, shares \| shares																			5,667,000
Series E Redeemable Convertible Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Proceeds from issuances of redeemable convertible preferred stock, net of issuance costs												$ 85,400,000
2014 Celgene Agreement \| Celgene
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Up-front, 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
Milestone revenue recognized						$ 10,000,000
Recognized of deferred revenue over the entire period					$ 8,200,000
2017 Celgene Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable		600,000								600,000					800,000				$ 600,000	800,000
2017 Celgene Agreement \| Celgene
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payment received		10,000,000
Milestone revenue recognized		10,000,000
Number of programs advancing through preclinical development \| Program					4
Option fee payment received					$ 12,500,000
Second option fee payment received					$ 12,500,000
Number of investigational new drug program \| Program					1
Recognized of deferred revenue over the entire period		11,400,000			$ 12,500,000					11,400,000					18,000,000				11,400,000	18,000,000
2017 Celgene Agreement \| Celgene \| Licensed Products
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum aggregate milestone and option fee payments eligible to receive																			295,000,000
2017 Celgene Agreement \| Celgene \| Other Licensed Products
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum aggregate milestone and option fee payments eligible to receive																			393,700,000
2018 Celgene Master Services Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Other revenue-related parties																			4,500,000
2018 Merck Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognized of deferred revenue over the entire period		53,000,000								53,000,000									53,000,000
Accounts receivable		900,000								900,000									900,000
2018 Merck Agreement \| Merck
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Recognized of deferred revenue over the entire period			$ 55,600,000
Number of research programs \| Program				3
Upfront payment received			$ 60,000,000
Number of target programs \| Program			2
Upfront payment received allocated to estimated significant incremental discount			$ 4,400,000
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 \| Common Stock \| Private Placement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock, 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 \| Series E Redeemable Convertible Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock, shares \| shares	74,794,315
Share issue price per share \| $ / shares	$ 0.2674
Proceeds from issuances of redeemable convertible preferred stock, net of issuance costs	$ 20,000,000
2018 Merck Agreement \| Merck \| Collaboration Revenue, Amortization of Up-front Payment
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue																			$ 7,000,000
2018 Merck Agreement \| Merck \| Collaboration Revenue, Research and Development Services
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total revenue																			1,500,000
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]
Recognized of deferred revenue over the entire period		1,700,000								1,700,000					5,900,000				$ 1,700,000	5,900,000
Up-front, nonrefundable and non-creditable payment received								$ 10,000,000
Estimated period of recognizing revenues from up-front payments																			2014-06
Maximum amount eligible to receive for each product developed																			$ 52,500,000
Accounts receivable		900,000								900,000					$ 800,000				900,000	$ 800,000
Supply Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Accounts receivable		49,000,000,000								49,000,000,000									49,000,000,000
Other revenue-related parties																			1,500,000
Research Development and Commercialization Agreement \| The Leukemia & Lymphoma Society, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Maximum contribution in clinical development			6,000,000
Initial milestone payment			500,000
Total milestone payments received			1,000,000
Milestone payment received against other income (expense)			900,000
Milestone payment received remaining other current liabilities		$ 100,000								$ 100,000									$ 100,000
Maximum aggregate payment			$ 19,500,000