6. Term Loan

On February 5, 2016, we entered into a loan and security agreement with Hercules Technology Growth Capital, Inc. ("HTGC"), as administrative agent and lender, and Hercules Technology III, L.P., as lender, pursuant to which the lenders agreed to make long-term loans to us in an aggregate principal amount of up to $40 million, subject to certain conditions. The lenders made an initial term loan to us on February 8, 2016 in the aggregate principal amount of $25 million. The term loan bears interest at the daily variable rate per annum equal to 6.00% plus the prime rate, or 9.5%, whichever is greater. We are required to make interest-only payments on the term loans through February 28, 2017, and beginning on March 1, 2017 we will be required to make amortizing payments of principal and accrued interest in equal monthly installments until the maturity date of the loan. Under the terms of the loan, we are required to maintain a minimum cash balance equal to the greater of (i) $10 million or (ii) forward three months projected cash burn. If we achieve certain milestones, we may request an additional term loan in an aggregate principal amount of up to $15 million no later than December 31, 2016, or such later date that HTGC otherwise determines in its sole discretion, but we do not expect to meet these milestones at this time. In connection with the loan and security agreement, we issued to the lenders warrants to purchase a total of 634,146 shares of our common stock at an exercise price of $2.05. These warrants are classified on the September 30, 2016 balance sheet as equity warrants with a fair value of $633,749 as determined at the date of issuance. All outstanding principal and accrued interest on the term loans will be due and payable in full on the maturity date of February 1, 2020, subject to the lenders' right to accelerate the term loans if we were to experience a "material adverse event" (as defined in the loan and security agreement).

As security for our obligations under the loan and securities agreement, we granted HTGC, as administrative agent, a security interest in substantially all of our existing and after-acquired assets except for our intellectual property and certain other excluded assets.

The following sets forth information regarding the current and long-term portion of the term loan:

	September 30, 2016
Term Loan Principal - Current	$	4,311,336
Issuance Cost - Current		(122,335	)
Loan Discount - Current		(626,423	)
Term Loan, Net - Current	$	3,562,578

Term Loan Principal	$	20,688,664
End Fee Payable		1,771,250
Long Term Issuance Cost		(353,919	)
Long Term Loan Discount		(1,908,003	)
Long Term Loan, Net	$	20,197,992

Interest expense on the term loan for the three-month and nine-month periods ended September 30, 2016 was $781,038 and $1,939,186, respectively. There was no interest expense in the 2015 comparative periods.