Years Ended December 31,

2019

2018

Balance, beginning of period

$

800,440

$

398,489

Inception of derivative financial instruments related to issuance of convertible notes payable

1,870,234

4,245,613

Inception of derivative financial instruments related to extinguishment and reissuance of convertible notes payable

51,169

—

Change in fair value of derivative financial instruments

(671,822

)

106,141

Conversion or extinguishment of derivative financial instruments

(1,058,733

)

(3,949,803

)

Balance, end of period

$

991,288

$

800,440