Pieris Pharmaceuticals, Inc. Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

Stockholders' equity - Narrative (Details)

Stockholders' equity - Narrative (Details) $ / shares in Units, $ in Thousands				1 Months Ended			3 Months Ended		12 Months Ended
	Apr. 01, 2020 shares	Mar. 31, 2020 $ / shares shares	Jan. 30, 2019 $ / shares shares	Nov. 30, 2019 USD ($) $ / shares shares	Aug. 31, 2019 USD ($)	Jun. 30, 2016 USD ($) $ / shares shares	Mar. 30, 2021 transaction partner	Sep. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Jan. 31, 2019 shares
Class of Stock [Line Items]
Common stock, shares authorized (shares)									300,000,000	300,000,000
Common stock, shares outstanding (shares)									56,002,815	55,212,437
Common stock, shares issued (shares)									56,002,815	55,212,437
Par value of common stock (USD per share) \| $ / shares									$ 0.001	$ 0.001
Preferred stock, shares authorized (shares)									10,000,000	10,000,000
Preferred stock, shares outstanding (shares)									14,429	11,429
Preferred stock, shares issued (shares)									14,429	11,429
Preferred stock, par value (USD per share) \| $ / shares									$ 0.001	$ 0.001
Cash proceeds from option exercises \| $									$ 291	$ 553
Cash proceeds from exercise of warrants \| $									$ 0	$ 246
Number of shares per unit (shares)						1
Gross sales proceeds from common stock \| $					$ 50,000
Warrant exercise period						5 years
Subsequent Event
Class of Stock [Line Items]
Number of transactions (in transactions) \| transaction							2
Number of partners (in partners) \| partner							2
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (shares)									2,907	2,907
Preferred stock, shares issued (shares)									2,907	2,907
Preferred stock, par value (USD per share) \| $ / shares						$ 0.001
Number of shares per unit (shares)						1
Shares issued upon conversion of convertible preferred stock (shares)						1,000
Price per unit issued (USD per share) \| $ / shares						$ 2.015
Proportion of beneficial ownership (as a percent)						9.99%
Series B Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (shares)									5,000	5,000
Preferred stock, shares issued (shares)									5,000	5,000
Series C Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (shares)									3,522	3,522
Preferred stock, shares issued (shares)									3,522	3,522
Series D Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding (shares)									3,000	0
Preferred stock, shares issued (shares)									3,000	0
Tranche A Warrants
Class of Stock [Line Items]
Number of shares called by warrants (shares)						0.4
Exercise price (USD per share) \| $ / shares						$ 2.00
Number of warrants						1
Tranche B Warrants
Class of Stock [Line Items]
Number of shares called by warrants (shares)						0.2
Exercise price (USD per share) \| $ / shares						$ 3.00
Number of warrants						1
Common shares
Class of Stock [Line Items]
Issuance of common stock resulting from exercise of stock options (shares)									149,000	279,000
Issuance of common stock resulting from exercise convertible securities (shares)										176,000
Convertible preferred shares \| Series B Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (shares)											5,000
Preferred stock, par value (USD per share) \| $ / shares			$ 0.001
Shares issued upon conversion of convertible preferred stock (shares)			1,000
Effective period of change to beneficial ownership limitation			61 days
Common stock ownership limit (as a percent)			9.99%
Beneficial ownership limitation (as a percent)			19.99%
Convertible preferred shares \| Series C Convertible Preferred Stock
Class of Stock [Line Items]
Shares issued upon conversion of convertible preferred stock (shares)				1,000
Common stock ownership limit (as a percent)				9.99%
Beneficial ownership limitation (as a percent)				19.99%
Convertible preferred shares \| Series D Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (shares)	3,000
Preferred stock, par value (USD per share) \| $ / shares		$ 0.001
Shares issued upon conversion of convertible preferred stock (shares)		1,000
Effective period of change to beneficial ownership limitation		61 days
Common stock ownership limit (as a percent)		9.99%
Beneficial ownership limitation (as a percent)		19.99%
Stock Exchange, Shares from Existing Shareholders \| Common shares
Class of Stock [Line Items]
Shares of common stock issued (shares)	3,000,000		5,000,000
Preferred Share Exchange
Class of Stock [Line Items]
Issue price per share (USD per share) \| $ / shares				$ 3.43
Beneficial conversion feature \| $				$ 2,800
Preferred Share Exchange \| Convertible preferred shares
Class of Stock [Line Items]
Shares of common stock issued (shares)	3,000		5,000
Private Placement
Class of Stock [Line Items]
Shares of common stock issued (shares)				9,014,960
Issue price per share (USD per share) \| $ / shares				$ 3.55
Shares of stock sold, gross consideration \| $				$ 32,000
Net proceeds from underwritten public offering \| $				$ 31,000
Number of shares per unit (shares)				1
Shares issued upon conversion of convertible preferred stock (shares)				0.001
Number of warrants included with each unit (in shares)				1
Exercise price (USD per share) \| $ / shares				$ 7.10
Period of determining volume weighted average stock price				10 days
Weighted average stock price commencing on trading day				3.00%
Effective period of change to beneficial ownership limitation				60 days
Private Placement \| Maximum
Class of Stock [Line Items]
Warrants and rights outstanding, term				5 years
Private Placement \| Series A Convertible Preferred Stock \| Two Thousand And Sixteen Private Investment In Public Equity
Class of Stock [Line Items]
Preferred stock, shares issued (shares)						4,963
At the market offering
Class of Stock [Line Items]
Shares of common stock issued (shares)								3,571,428
Issue price per share (USD per share) \| $ / shares								$ 2.80
Net proceeds from underwritten public offering \| $								$ 10,000
Gross sales proceeds from common stock \| $								$ 9,700
Sales commissions and fees								3.00%
Securities Purchase Agreement
Class of Stock [Line Items]
Number of capital units sold in private placement transaction (units)						8,188,804
Price per unit issued (USD per share) \| $ / shares						$ 2.015
Gross proceeds from private placement units sold \| $						$ 16,500
Net proceeds from private placement units sold \| $						$ 15,300
Two Thousand And Sixteen Private Investment In Public Equity
Class of Stock [Line Items]
Shares of common stock issued (shares)						3,225,804