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 Thousands				1 Months Ended	9 Months Ended
	Aug. 09, 2019	Jul. 31, 2019	Jan. 30, 2019	Nov. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Nov. 12, 2019	Nov. 01, 2019	Jan. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Shares of common stock outstanding (shares)					49,392,706					54,151,219
Shares of preferred stock outstanding (shares)					7,907
Par value of common stock (USD per share)	$ 0.001				$ 0.001					$ 0.001
Preferred stock authorized (shares)					10,000,000					10,000,000
Par value of preferred stock (USD per share)					$ 0.001					$ 0.001
Gross sales proceeds from common stock	$ 50,000				$ 0	$ 47,207
Common Stock \| Stock Exchange, Shares from Existing Shareholders
Class of Stock [Line Items]
Shares of stock sold (in shares)			5,000,000
Preferred Stock \| Preferred Share Exchange
Class of Stock [Line Items]
Shares of stock sold (in shares)			5,000
Series B Preferred Stock
Class of Stock [Line Items]
Shares of preferred stock outstanding (shares)					5,000					0
Series B Preferred Stock \| Preferred Stock
Class of Stock [Line Items]
Preferred stock authorized (shares)									5,000
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
Par value of preferred stock (USD per share)					$ 0.001
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)		931,896
Subsequent Event \| Private Placement
Class of Stock [Line Items]
Shares of stock sold (in shares)				9,014,960
Stock issued upon conversion (shares)								1,000
Shares of stock sold, price per share (in dollars per share)								$ 3.55
Shares of stock sold, gross consideration				$ 32,000
Shares of stock sold, net consideration				$ 31,100
Number of warrants included with each unit (in shares)				1
Warrants, exercise price (in dollars per share)							$ 7.10
Subsequent Event \| Common Stock \| Private Placement
Class of Stock [Line Items]
Number of shares included with each unit (in shares)				1
Subsequent Event \| Series C Convertible Preferred Stock \| Preferred Stock \| Private Placement
Class of Stock [Line Items]
Number of shares included with each unit (in shares)				0.001
Minimum \| Subsequent Event \| Private Placement
Class of Stock [Line Items]
Warrants, term							60 days
Maximum \| Subsequent Event \| Private Placement
Class of Stock [Line Items]
Warrants, term							5 years