8. Debt and Warrants

Warrants Issued with the Preferred Stock

In February 2014, the Company closed its first equity round of financing and sold 2,224,991 shares of Series A convertible preferred stock at a price of $2.2472 per share. The pre-money valuation was in excess of $3.0 million setting the exercise price of the Warrants at 75% of the purchase price paid by the investors, or $2.5281 (as adjusted for the 1-for-1.5 reverse stock split approved in October 2014) per share. As such, the fair value of the Warrants, $6,895, was recorded as equity in February 2014. The Warrants were valued at $6,895 using the Black-Scholes model with the following assumptions: exercise price of $2.5281, term of five years, volatility of 64%, dividend yield of 0%, and risk-free interest rate of 1.82%. Based on the fair value of the Warrants, the Company used the residual value of the total proceeds from the issuance of the Notes and Warrants to record the Notes on the balance sheet as of issuance of the Notes. Thus, the amount recorded, in the aggregate, for the Notes on issuance was $518,105, net. The debt discount of $6,895 is recorded as interest expense over the five-year term of the Warrants.

Convertible Notes and Warrants

2013 Convertible Notes

From July through September 2013, the Company issued four convertible promissory notes (collectively the "Notes") for gross aggregate proceeds of $525,000 to various third-party lenders. The Notes bore interest at 8% per annum. The Notes automatically matured and the entire outstanding principal amount, together with accrued interest, was due and payable in cash at the earlier of July 8, 2015 (the "Maturity Date") or ten business days after the date of consummation of the initial closing of a first equity round of financing. The Company consummated a first equity round of financing prior to the Maturity Date with a pre-money valuation of greater than $3.0 million, and, accordingly, principal and accrued interest was converted into shares of common stock at 75% of the purchase price paid by such equity investors. These notes were all converted to common stock in February 2014 upon the issuance of the convertible preferred stock. In February 2014, in connection with the first equity round of financing and issuance of the Series A convertible preferred stock, the noteholders exercised their option to convert their Notes into 207,664 shares of common stock and accrued interest was paid in cash to the noteholders. The accreted interest expense related to the discount on the Notes was $1,443 for the period from January 1, 2014 to the conversion date of the Notes. Upon conversion, the entire remaining debt discount of $4,071 was recorded as interest expense.

In connection with the Notes, the Company issued to the noteholders warrants, which became exercisable to purchase an aggregate of 207,664 shares of common stock as of the issuance of the first equity round of financing (the "Warrants"). The Warrants are fully exercisable from the initial date of the first equity round of financing and have a five-year term subsequent to that date.

2014 Convertible Notes

On June 2, 2014, pursuant to a convertible note purchase agreement, the Company issued convertible promissory notes in the aggregate principal amount of $300,000 to two accredited investors, including a convertible promissory note for $200,000 to a board member to which Series A preferred stock was sold. These notes accrued interest at 3% per annum and automatically were to mature on June 1, 2015. Accrued interest was to be paid in cash upon maturity. Upon the closing of the IPO, the outstanding principal amount automatically converted into 53,571 shares common stock at $5.60, as amended in March 2015. Upon issuance, the Company analyzed the beneficial nature of the conversion terms and determined that a beneficial conversion feature ("BCF") existed because the effective conversion price on issuance of the notes was less than the fair value at the time of the issuance. The Company calculated the value of the BCF using the intrinsic method and recorded a BCF of $75,000 as a discount to the notes payable and to additional paid-in capital. For the year ended December 31, 2015 and 2014, the Company amortized $31,250 and $6,250, respectively, of the discount, which has also been recorded as interest expense.

On July 16, 2014, pursuant to a convertible note purchase agreement, the Company issued a convertible promissory note in the principal amount of $150,000 to an accredited investor. This note accrued interest at 3% per annum and automatically was to mature on June 1, 2015. Accrued interest was to be paid in cash upon maturity. Upon the closing of the IPO, the outstanding principal amount automatically converted into 26,785 shares of common stock at $5.60, as amended in March 2015. Upon issuance, the Company analyzed the beneficial nature of the conversion terms and determined that a BCF existed because the effective conversion price was less than the fair value at the time of the issuance. The Company calculated the value of the BCF using the intrinsic method and recorded a BCF of $37,500 as a discount to the notes payable and to additional paid-in capital. For the year ended December 31, 2015, the Company amortized $17,857 of the discount, which has also been recorded as interest expense.

In connection with the Transfer Agreement (Note 7) the Company issued fully vested and immediately exercisable warrants to the Manufacturer to purchase 16,666 shares of common stock at 90% of the IPO price, amended to $6.30 in March 2015, for a period of five years. The fair value of the warrants, $37,840, was recorded as research and development expense and additional paid-in capital in June 2014. The warrants were originally valued using the Black-Scholes model with the following assumptions: stock price of $4.83, exercise price of $4.35, term of five years, volatility of 49%, dividend yield of 0%, and risk-free interest rate of 1.64%.

On December 23, 2014, pursuant to a convertible note purchase agreement, the Company issued convertible promissory notes in the aggregate principal amount of $650,000 to three accredited investors, including a convertible promissory note for $250,000 to the same board member to which the June 2, 2014 $200,000 convertible promissory note was issued and to which Series A preferred stock was sold. These notes accrued interest at 12% per annum and became payable within thirty days following the IPO. Upon consummation of the Company's IPO, the noteholders converted the notes into 116,070 shares of common stock at a conversion price equal to 80% of the IPO price, amended to $5.60 in March 2015. In connection with these notes, the Company also issued the lenders a fully vested warrant to purchase shares of the Company's common stock at an exercise price equal to 80% of the IPO price, amended to $5.60 in March 2015. These warrants entitle the noteholders to purchase 58,035 shares of common stock. The fair value of the warrants, $147,943, was recorded as a debt discount and liability at December 23, 2014. The Company amortized the remaining $141,890 of this discount during the year ended December 31, 2015. The warrants were originally valued using the Black-Scholes model with the following assumptions: stock price of $4.59, exercise price of $4.15, term of three years, volatility of 49%, dividend yield of 0%, and risk-free interest rate of 1.10%. Based on the circumstances, the value derived using the Black-Scholes model approximated that which would be obtained using a lattice model. The debt discount was be recorded as interest expense over the one hundred ninety days from issuance of the notes through their first maturity date of July 31, 2015, beginning in January 2015. The Company analyzed the beneficial nature of the conversion terms and determined that a BCF existed because the effective conversion price was less than the fair value at the time of the issuance. The Company calculated the value of the BCF using the intrinsic method. A BCF of $502,057 has been recorded as a discount to the notes payable and to additional paid-in capital. For the year ended December 31, 2015, the Company amortized the remaining $484,326 of the BCF which has also been recorded as interest expense.

2015 Convertible Notes

In February 2015, the Company issued convertible promissory notes to two accredited investors in the aggregate principal amount of $250,000. These notes were issued pursuant to the convertible note purchase agreement dated December 23, 2014. Principal and interest of $103,912 was paid in May 2015 for $100,000 of these notes.

The Company's remaining outstanding note of $150,000 is payable to Serious Change II LP at an effective simple interest rate of 12% per annum, and is due in full on July 31, 2016. The note is included in notes payable in the Company's balance sheet. The Company has accrued interest of $15,879, which is included in accrued liabilities in the Company's balance sheet. The note remains outstanding as Serious Change II LP elected not to convert the note as per the terms of the agreement.

In March 2015, the Company entered into a non-binding letter of intent with Dechra Pharmaceuticals PLC ("Dechra"). In connection therewith, Dechra paid the Company $1.0 million. At March 31, 2015, the Company had recorded this amount as a loan advance on the balance sheet. In April 2015, Dechra purchased $1.0 million of convertible promissory notes from the Company, the terms of which provided that such notes were to be converted into shares of the Company's common stock upon the closing of an IPO at a conversion price of $5.60 per share. In connection with the purchase of the notes, the Company issued Dechra a warrant to purchase 89,285 shares at $5.60 per share, which expires December 31, 2017. The notes accrued simple interest of 12% per annum and, upon consummation of the Company's IPO in May 2015, converted into 178,571 shares of the Company's common stock. The Company analyzed the beneficial nature of the conversion terms and determined that a BCF existed because the effective conversion price was less than the fair value at the time of the issuance. The Company calculated the value of the BCF using the intrinsic method. A BCF of for the full face value was recorded as a discount to the notes payable and to additional paid-in capital. For the year ended December 31, 2015, the Company amortized the entire BCF of $1.0 million which has also been recorded as interest expense.

As of December 31, 2015 and 2014, the convertible notes payable obligations were as follows:

	December 31, 2015		December 31, 2014
Notes payable	$	150,000	$	1,100,000
Unamortized note discount		—		(675,326	)

Net debt obligation	$	150,000	$	424,674

Interest expense on the convertible notes payable was as follows:

	December 31, 2015		December 31, 2014
Nominal interest	$	70,619	$	9,292
Amortization of debt discount		1,925,326		87,174

	$	1,995,945	$	96,466

At December 31, 2015 and 2014, interest payable on convertible notes payable was $75,999 and $29,276, respectively.

Notes Payable—Bridge Loans

On October 30, 2014, the Company entered into a standby bridge financing agreement with two lenders, which was amended and restated on December 3, 2014, which provided a loan commitment in the aggregate principal amount of $1.0 million (the "Bridge"). Proceeds to the Company were net of a $100,000 debt discount under the terms of the Bridge and net of $104,000 of debt issuance costs. This debt discount and debt issuance costs were recorded as interest expense using the effective interest method, over the six month term of the Bridge. The Bridge became payable upon the IPO. The Bridge was repaid in May 2015, including interest thereon in an amount of $1,321,600. In connection with the Bridge, the lenders were granted warrants to purchase that number of shares of the Company's common stock determined by dividing $1.0 million by the exercise price of 80% of the IPO price, amended to $5.60 in March 2015. The fair value of the warrants, $505,348, was originally recorded as a debt discount and liability at December 3, 2014. The warrants were originally valued using the Black-Scholes model with the following assumptions: stock price of $5.01, exercise price of $5.23, term of five years, volatility of 63%, dividend yield of 0%, and risk-free interest rate of 1.61%. Based on the circumstances, the value derived using the Black-Scholes model approximated that which would be obtained using a lattice model. The debt discount was recorded as interest expense over the six month term of the Bridge. Of the aggregate debt discount of $605,348 (warrants and original $100,000 discount), $521,291 was recorded as interest expense during the year ended December 31, 2015. Additional financing costs of $104,000 were incurred related to the Bridge and deferred on closing. These are being recognized as interest expense over the six-month term of the Bridge using the effective interest method. During the year ended December, 2015, the remaining $86,667 of these deferred financing charges was recorded as interest expense.

As of December 31, 2015 and 2014, the notes payable obligation was as follows:

	December 31, 2015		December 31, 2014
Notes Payable	$	—	$	1,000,000
Unamortized note discount		—		(521,291	)
Debt issuance costs		—		(86,667	)

Net debt obligation	$	—	$	392,042

Interest expense on the notes payable-bridge loans was as follows:

	December 31, 2015		December 31, 2014
Nominal Interest	$	100,000	$	20,000
Amortization of debt discount		521,291		84,057
Repayment premium		201,600		—
Debt issuance costs		86,667		17,333

	$	909,558	$	121,390

Standby Line of Credit

In August 2014, the Company entered into a standby line of credit with an accredited investor for up to $1.0 million pursuant to a Line of Credit and Loan Agreement dated August 26, 2014. In connection with the entry into the standby line of credit, the Company issued the lender a fully vested warrant to purchase 33,333 shares of common stock at an exercise price equal to 80% of the IPO price, amended to $5.60 in March 2015, which expires in August 2016. The fair value of the warrants, $114,300, was recorded as interest expense and additional paid-in capital in August 2014. The warrants were originally valued using the Black-Scholes model with the following assumptions: stock price of $8.00, exercise price of $6.40, term of two years, volatility of 52%, dividend yield of 0%, and risk-free interest rate of 0.52%. The line of credit expired on March 31, 2015 and there have been no drawdowns under the facility.

Long-term Debt

In August 2015, the Company entered into a loan and security agreement with a lender for up to $8.0 million, which provided for an initial loan commitment of $6.0 million. The loan agreement requires the Company to maintain $4.5 million of the proceeds in cash, which may be reduced or eliminated on the achievement of certain milestones. An additional $2.0 million is available contingent on the achievement of certain further milestones. The agreement has a term of three years, with interest only payments through February 29, 2016. Thereafter, principal and interest payments will be made with an interest rate of 9.9%. Additionally, there will be a balloon payment of $560,000 on August 1, 2018. This amount is being recognized over the term of the loan agreement and the effective interest rate, considering the balloon payment, is 15.0%. Proceeds to the Company were net of a $134,433 debt discount under the terms of the loan agreement. This debt discount is being recorded as interest expense, using the interest method, over the term of the loan agreement. Under the agreement, the Company is entitled to prepay principal and accrued interest upon five days prior notice to the lender. In the event of prepayment, the Company is obligated to pay a prepayment charge. If such prepayment is made during any of the first twelve months of the loan agreement, the prepayment charge will be (a) during such time as the Company is required to maintain a minimum cash balance, 2% of the minimum cash balance amount plus 3% of the difference between the amount being prepaid and the minimum cash balance, and (b) after such time as the Company is no longer required to maintain a minimum cash balance, 3% of the amount being prepaid. If such prepayment is made during any time after the first twelve months of the loan agreement, 1% of the amount being prepaid.

As of December 31, 2015 and 2014, the net long-term debt obligation was as follows:

	December 31, 2015			December 31, 2014
Debt and unpaid accrued end-of-term payment	$	6,115,797		$	—
Unamortized note discount		(106,635	)		—
Unamortized debt issuance costs		(206,234	)		—

Net debt obligation	$	5,802,927		$	—


Current portion of long-term debt	$	1,707,899		$	—
Long-term debt, net of discount		4,095,028			—

Total	$	5,802,927		$	—

Future principal payments under the long-term debt are as follows:

	Amount
Years ending December 31,
2016	$	1,832,500
2017		2,409,780
2018		1,757,720

Total principal payments	$	6,000,000

The obligation at December 31, 2015 includes an end-of-term payment of $560,000, which accretes over the life of the loan as interest expense. As a result of the debt discount and the end-of-term payment, the effective interest rate for the loan differs from the contractual rate.

Interest expense on the long-term debt was as follows:

	December 31, 2015		December 31, 2014
Nominal interest	$	224,400	$	—
Amortization of debt discount		27,798		—
Accretion of end-of-term payment		115,797		—
Debt issuance costs		43,789		—

	$	411,784	$	—

At the IPO, the Company's outstanding warrants to purchase convertible preferred stock were all converted to warrants to purchase common stock.

The Company's warrant activity is summarized as follows:

	December 31, 2015		December 31, 2014
Warrants outstanding at January 1		494,267		207,664
Warrants issued		254,605		286,603

Warrants outstanding at December 31		748,872		494,267