Borrowings

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Borrowings

7. Borrowings

On September 30, 2016, the Company entered into a loan agreement with Solar, in its capacity as administrative and collateral agent and as lender. Pursuant to the loan agreement, Solar was providing the Company with a 48-month secured term loan in the amount of $15.0 million.  The term loan bore interest at a floating rate equal to the LIBOR rate in effect plus 8.49%.

Pursuant to the loan agreement, on September 30, 2016 (the "Closing Date"), the Company issued to Solar a warrant (the “Solar Warrant”) to purchase an aggregate of up to 122,435 shares of the Company’s common stock at an exercise price of $3.6754 per share. The Solar Warrant will expire five years from the date of the grant.  The Solar Warrant is classified as equity and was recorded at its relative fair value at issuance in the stockholders' equity section of the balance sheet (See Note 9).

On March 7, 2019, the Company entered into a Senior Convertible Note Purchase Agreement (the “Note Purchase Agreement”) with Puissance Life Science Opportunities Fund VI (Puissance).  Pursuant to the Note Purchase Agreement, on March 7, 2019, the Company issued and sold to the investor $16 million aggregate principal amount of its 6.0% Convertible Senior Notes due 2025 (the “Note”) and the Company used the cash proceeds to pay the remaining outstanding Solar Term Loan in full (see Note 14 for further details).In accordance with ASC 470-10-45-14(a), the Company reclassified the short-term portion of the Solar Term Loan on the balance sheet to long-term given the Company had the intent and ability to refinance the short-term obligation on a long-term basis.