10.	Common Stock and Stock-Based Compensation

Reverse Stock Split

Following approval by our shareholders at a meeting held on

April 15, 2019,

April 30, 2019,

we effected a

one

-for-

five hundred

reverse split of our common stock by the filing of an amendment to our certificate of incorporation with the State of Delaware. All share and per share information in our condensed consolidated financial statements and notes that relate to our common stock has been retroactively restated to reflect the reverse stock split.

Common Stock Transactions

As discussed in Note

during the

nine

-month period ended

September 30, 2019,

we issued

95,147,421

shares of our common stock pursuant to conversions our Series C, Series F and Series H Preferred Stock.

During the

nine

-month period ended

September 30, 2019,

we issued

41,954

shares of our common stock in exchange for consulting services. See “Stock-Based Compensation Expense” below.

Stock Options

During the

nine

months ended

September 30, 2019,

there were

transactions involving our stock option plans. As of

September 30, 2019,

there are

28,800

stock options outstanding (

$53.99/share

weighted-average exercise price),

13,585

of which are exercisable at that date (

$93.92/share

weighted-average exercise price).

Stock Purchase Warrants

During the

nine

months ended

September 30, 2019,

we issued an aggregate of

100,002

stock purchase warrants in connection with the sale of our Series G Preferred Stock as discussed above. As of

September 30, 2019,

there are

294,302

stock purchase warrants outstanding (

$7.50/share

weighted-average exercise price),

227,634

of which are exercisable at that date (

$7.50/share

weighted-average exercise price).

Stock-Based Compensation Expense

Stock-based compensation expense related to our stock option plans was

$26,348

and

$79,664

during the

three

-month and

nine

-month periods ended

September 30, 2019,

respectively, as compared to

$85,370

and

$132,569,

respectively, during the same periods of

2018.

Stock-based compensation expense related to stock options is recognized on a straight-line basis over the requisite service period for the award and is allocated to research and development expense or general and administrative expense based upon the related employee classification. As of

September

30,

2019,

there was

$130,719

of unrecognized compensation expense related to stock options, which we expect to recognize over a weighted average period of

1.6

years.

During the

three

-month and

nine

-month periods ended

September 30, 2019

we recorded stock-based compensation expense of

$6,000

and

$211,080,

respectively, associated with common stock issued for consulting and financial advisory services, as compared to

$57,143

and

$142,856,

respectively, during the same periods of

2018.