8. Convertible Senior Secured Notes

The table below summarizes activity related to the Notes from their issuance on May 3, 2013 through September 30, 2017, in thousands:

Gross proceeds	$	90,000
Initial value of interest make-whole derivative reported as debt discount	(9,270		)
Conversion option reported as debt discount and APIC	(22,336		)
Conversion of debt to equity - principal	(85,425		)
Conversion of debt to equity - accretion of debt discount and deferred financing costs	25,767
Accretion of debt discount and deferred financing costs	5,429

December 31, 2016 carrying value	4,165

Conversion of debt to equity - principal	(4,575		)
Conversion of debt to equity - accretion of debt discount and deferred financing costs	360
Accretion of debt discount and deferred financing costs	50

September 30, 2017 carrying value, unaudited	$	—

During the nine months ended September 30, 2017, approximately $4.6 million of the Notes were presented to the Company for conversion. Accordingly, the Company issued approximately 0.9 million shares of common stock in conversion of the principal amount of the Notes. As a result of the conversions, the Company incurred a loss of approximately $0.3 million on extinguishment of debt during the nine months ended September 30, 2017, which is included as a separate component of other income (expense) on the Consolidated Statement of Operations. During the nine months ended September 30, 2016, consequent to approximately $2.0 million in note conversions, the Company incurred a loss of approximately $0.4 million on extinguishment of debt.