Debt

Equipment Financing Obligations

In April 2010, the Company entered into an amendment to its credit facility to provide for up to $4.0 million to finance equipment purchases and other related expenses, with borrowing thereunder secured by certain fixed assets of the Company and repayable over 48 months. Until the credit facility expired in March 2011, the Company utilized $2.2 million of the credit facility, which bore interest on a weighted average basis of 6.7%. As of December 31, 2013, in aggregate, $0.3 million was outstanding and secured by certain fixed assets which had a remaining net book value of $0.4 million. As of December 31, 2014, the loans under the credit facility were fully repaid.

Convertible Debt from Related Party

In September 2011, the Company entered into a convertible note loan agreement with Bio-Techne Corporation, formerly Techne Corporation (Bio-Techne), one of its principal stockholders, pursuant to which the Company issued a convertible note to Bio-Techne with a principal amount of $10 million and bearing interest at a rate of 5.0% per annum and a maturity date in September 2021. The Company accounted for the note at fair value, under a fair value option available under generally accepted accounting principles. The note was remeasured to fair value every reporting period while outstanding. In February 2012, the Company completed its initial public offering, and as such, all outstanding principal and accrued and unpaid interest automatically converted into shares of common stock at a conversion price equal to the initial public offering price of $10.00.

Interest expense for the years ended December 31, 2014 and 2013 represents interest expense from equipment financing obligations. The following table summarizes interest expense in the consolidated statement of operations for the year ended December 31, 2014, 2013 and 2012 (in thousands):


	Year Ended December 31,
	2014		2013		2012
Interest expense
Interest expense from convertible debt from related party	$	—	$	—	$	711
Other		24		59		83

Total interest expense	$	24	$	59	$	794