|12 Months Ended|
Dec. 31, 2020
|Warrants and Rights Note Disclosure [Abstract]|
On November 20, 2020, the Company entered into Warrant Exchange and Amendment Agreements with certain holders of Exchange Warrants. Pursuant to the Exchange Agreements, the Holders agreed to amend each of the Purchase Agreements so that the Company will no longer be prohibited from effecting or agreeing to affect any Variable Rate Transactions. In addition, pursuant to the Exchange Agreements, the Company offered the Holders the opportunity to exchange in full all their Exchange Warrants in exchange for 0.2 shares of the Company’s common stock, par value $0.0001 per share for each share of Common Stock issuable upon exercise of an Exchange Warrant being exchanged. Further, the Company agreed not to issue or agree to issue any Common Stock or Common Stock equivalents for a period of five trading days from the effective date of the Exchange Agreements, subject to certain exceptions. The Company issued an aggregate of 11 thousand Exchange Shares pursuant to the Exchange Agreements. The Company recognized a gain on the exchange of $2 thousand which is recorded in change in the fair value of warrant liability at December 31, 2020.
On June 8, 2019, warrants to purchase 123 thousand shares of the Company's common stock, referred to below as the 2017 Offering, expired.
In January 2019, the Company issued warrants to purchase 31 thousand and 36 thousand shares of its common stock at $7.43 and $7.59 per share, respectively, in conjunction with its 2019 Offerings described in Note 11. On October 28, 2020. the Company issued 94 thousand warrants to purchase 94 thousand shares of its common stock at $2.42 in conjunction with its October 28, 2020 offering described in note 11.
The following table summarizes the warrant activity for the years ending December 31, 2020 and 2019 (in thousands except exercise price):
AThese warrants are subject to fair value accounting and contain a contingent net cash settlement feature. See Note 14.
BWeighted average exercise prices are as of December 31, 2020.