Derivative Warrant Liability

The following sets forth information pertaining to shares underlying warrants outstanding as of

December 31, 2018:

	Issuance Date	Expiration Date	Exercise Price as of December 31, 2018		Shares Underlying Warrants on Issuance Date		Shares Issued upon Warrant Exercises as of December 31, 2018		Shares Underlying Warrants Outstanding as of December 31, 2018 (1)
2014 Warrants	08/05/2014	08/05/2019	$	65.50		2,500		1,526		974
Series A Warrants	02/03/2015	02/03/2020	$	3.80		5,542		5,222		320
Series C Warrants	05/19/2015	05/19/2020	$	53.43		1,075		–		1,075
Series D Warrants	12/11/2015	12/11/2020	$	40.00		25,125		25,078		47
Series F Warrants	04/01/2016	04/01/2021	$	40.00		25,733		11,692		14,041
Series I Warrants	09/13/2016	09/13/2021	$	220.00		35,650		–		35,650
Series K Warrants	02/17/2017	2/17/2022	$	3.80		312,516		308,660		3,856
						408,141		352,178		55,963

(

)

This table does

not

include equity-classified warrants issued in

2011,

to purchase

shares of common stock with a strike price of

$345

per share.

The agreements governing the above warrants include the following terms:

•

certain warrants have exercise prices which are subject to adjustment for certain events, including the issuance of stock dividends on the Company’s common stock and, in certain instances, the issuance of the Company’s common stock or instruments convertible into the Company’s common stock at a price per share less than the exercise price of the respective warrants;

•

warrant holders

may

exercise the warrants through a cashless exercise if, and only if, the Company does

not

have an effective registration statement then available for the issuance of the shares of its common stock. If an effective registration statement is available for the issuance of its common stock, a holder

may

only exercise the warrants through a cash exercise;

•

the exercise price and the number and type of securities purchasable upon exercise of the warrants are subject to adjustment upon certain corporate events, including certain combinations, consolidations, liquidations, mergers, recapitalizations, reclassifications, reorganizations, stock dividends and stock splits, a sale of all or substantially all of the Company’s assets and certain other events; and

•

in the event of an extraordinary transaction (as defined in the respective warrant agreements), generally including any merger with or into another entity, sale of all or substantially all of the Company’s assets, tender offer or exchange offer, or reclassification of its common stock, in which the successor entity (as defined in the respective warrant agreements) that assumes the warrant is

not

a publicly traded company, the Company or any successor entity will pay the warrant holder, at such holder’s option, exercisable at any time concurrently with or within

days after the consummation of the extraordinary transaction, an amount of cash equal to the value of such holder’s warrants as determined in accordance with an appropriate valuation model and the terms of the respective warrant agreement.

Based on these terms, the Company has determined that all warrants issued since

2013

(the “Warrants”) qualify as derivatives and, as such, are presented as a derivative warrant liability on the consolidated balance sheets and recorded at fair value each reporting period. The fair value of the Warrants was estimated to be

$0.02

and

$2.0

million as of

December 31, 2018

and

December

31,

2017,

respectively. The decrease in the estimated fair value of the Warrants outstanding as of

December 31, 2018

represents an unrealized gain which has been recorded as a gain from the change in fair value of derivative warrant liability in the consolidated statements of operations.

During the

twelve

months ended

December 31, 2018,

common stock was issued as a result of exercise of Warrants as described below:

	Twelve Months Ended December 31, 201 8
	Common Stock Issued		Proceeds
Series A Warrants		251		1,054
Series K Warrants		300,660		1,262,712
		300,911	$	1,263,766