Pieris Pharmaceuticals, Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Narrative (Details)

Stockholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions				1 Months Ended		12 Months Ended
	Mar. 31, 2020	Jul. 31, 2019	Jan. 30, 2019	Nov. 30, 2019	Aug. 31, 2019	Dec. 31, 2019	Nov. 12, 2019	Jan. 31, 2019
Class of Stock [Line Items]
Common stock authorized (shares)	300,000,000					300,000,000
Common stock issued (shares)	55,212,477					55,212,437
Common stock outstanding (shares)	55,212,477					55,212,437
Par value of common stock (USD per share)	$ 0.001					$ 0.001
Preferred stock authorized (shares)	10,000,000					10,000,000
Preferred stock issued (shares)	11,429					11,429
Preferred stock outstanding (shares)	11,429					11,429
Par value of preferred stock (USD per share)	$ 0.001					$ 0.001
Number of shares included with each unit (in shares)				1
Number of warrants included with each unit (in shares)				1
Gross sales proceeds from common stock					$ 50.0
Preferred Share Exchange
Class of Stock [Line Items]
Shares of stock sold, price per share (in dollars per share)						$ 3.43
Beneficial conversion feature						$ 2.8
Private Placement
Class of Stock [Line Items]
Shares of stock sold (in shares)				9,014,960
Stock issued upon conversion (shares)				0.001
Notice period before increase of Beneficial Ownership Limitation				60 days
Shares of stock sold, price per share (in dollars per share)				$ 3.55
Shares of stock sold, gross consideration				$ 32.0
Shares of stock sold, net consideration				$ 31.0
Warrants, exercise price (in dollars per share)				$ 7.10
Common Stock
Class of Stock [Line Items]
Number of securities called by each warrant				1
Common Stock \| Stock Exchange, Shares from Existing Shareholders
Class of Stock [Line Items]
Shares of stock sold (in shares)	3,000,000		5,000,000
Preferred Stock \| Preferred Share Exchange
Class of Stock [Line Items]
Shares of stock sold (in shares)	3,000		5,000
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock issued (shares)						2,907
Preferred stock outstanding (shares)	2,907					2,907
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock issued (shares)						5,000
Preferred stock outstanding (shares)	5,000					5,000
Series B Preferred Stock \| Preferred Stock
Class of Stock [Line Items]
Preferred stock authorized (shares)								5,000
Series C Preferred Stock
Class of Stock [Line Items]
Preferred stock issued (shares)						3,522
Preferred stock outstanding (shares)	3,522					3,522
Series D Preferred Stock \| Preferred Stock
Class of Stock [Line Items]
Preferred stock authorized (shares)	3,000
Par value of preferred stock (USD per share)	$ 0.001
Stock issued upon conversion (shares)	1,000
Common stock ownership limit (as a percent)	9.99%
Beneficial ownership limitation (as a percent)	19.99%
Notice period before increase of Beneficial Ownership Limitation	61 days
2019 Employee, Director and Consultant Equity Incentive Plan
Class of Stock [Line Items]
Shares of stock authorized pursuant to the 2019 Plan (shares)		2,750,000
2018 Plan
Class of Stock [Line Items]
Shares of stock terminated under the 2018 Plan (shares)		654,341
Maximum \| Private Placement
Class of Stock [Line Items]
Warrants, term							5 years