Marketable Securities and Fair Value Measurements

The guidance regarding fair value measurements establishes a three-tier fair value hierarchy which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions.

Assets and liabilities are classified based on the lowest level of input that is significant to the fair value measurements. The Company reviews the fair value hierarchy classification on a quarterly basis. Changes in the ability to observe valuation inputs may result in a reclassification of levels for certain securities within the fair value hierarchy. The Company did not have any transfer of assets and liabilities between Level 1, Level 2 and Level 3 of the fair value hierarchy during the six months ended June 30, 2015 or 2014.

The following table presents the Company’s assets and liabilities that are measured at fair value on a recurring basis as of June 30, 2015:



	Fair Value Measurements at
	June 30, 2015
	Total		Using Quoted Prices in Active Markets for Identical Assets (Level 1)		Using Significant Other Unobservable Inputs (Level 2)		Using Significant Unobservable Inputs (Level 3)
Assets:
Money market funds	$	66,460,760	$	66,460,760	$	—	$	—
Mutual funds	58,235,791		—		58,235,791		—
US corporate debt securities	25,955,991		—		25,955,991		—
Municipal bonds	104,039		—		104,039		—
Investment in affiliated entity	18,849,647		18,849,647		—		—
Common stock warrants	186,500		—		—		186,500
Total Assets	$	169,792,728	$	85,310,407	$	84,295,821	$	186,500
Liabilities:
Common stock warrants	$	1,710,229	$	—	$	—	1,710,229
Total Liabilities	$	1,710,229	$	—	$	—	$	1,710,229

The following table presents the Company’s assets and liabilities that are measured at fair value on a recurring basis as of December 31, 2014:



	Fair Value Measurements at
	December 31, 2014
	Total		Using Quoted Prices in Active Markets for Identical Assets (Level 1)		Using Significant Other Unobservable Inputs (Level 2)		Using Significant Unobservable Inputs (Level 3)
Assets:
Money market funds	$	36,474,066	$	36,474,066	$	—	$	—
Mutual funds	29,273,635		—		29,273,635		—
US corporate debt securities	23,802,339		—		23,802,339		—
Investment in affiliated entity	12,340,811		12,340,811		—		—
Common stock warrants	550,000		—		—		550,000
Total Assets	$	102,440,851	$	48,814,877	$	53,075,974	$	550,000
Liabilities:
Common stock warrants	$	2,022,729	$	—	$	—	$	2,022,729
Total Liabilities	$	2,022,729	$	—	$	—	$	2,022,729

Level 1 assets include money market funds held by the Company that are valued at quoted market prices, as well as the Company’s investment in GeneOne, for which the fair value is based on the market value of 1,644,155 common shares on June 30, 2015 and December 31, 2014, listed on the Korean Stock Exchange. The Company accounts for its investment at fair value on a recurring basis.

Level 2 assets at June 30, 2015 include US corporate debt securities, mutual funds and municipal bonds held by the Company that are initially valued at the transaction price and subsequently valued, at the end of each reporting period, typically utilizing market observable data. The Company obtains the fair value of its Level 2 assets from a professional pricing service, which may use quoted market prices for identical or comparable instruments, or inputs other than quoted prices that are observable either directly or indirectly. The professional pricing service gathers quoted market prices and observable inputs from a variety of industry data providers. The valuation techniques used to measure the fair value of the Company's Level 2 financial instruments were derived from non-binding market consensus prices that are corroborated by observable market data, quoted market prices for similar instruments, or pricing models such as discounted cash flow techniques. The Company validates the quoted market prices provided by the primary pricing service by comparing their assessment of the fair values of the Company's investment portfolio balance against the fair values of the Company's investment portfolio balance obtained from an independent source.

Level 3 assets at June 30, 2015 include two warrants received by the Company to purchase shares of common stock of OncoSec Medical Incorporated (“OncoSec”), in connection with the first and second amendments to the Asset Purchase Agreement between the Company and OncoSec signed in September 2011 and March 2012, respectively. The first warrant to purchase 50,000 shares of common stock of OncoSec has a contractual life of five years with an exercise price of $24.00 per share. The second warrant to purchase 150,000 shares of common stock of OncoSec has a contractual life of five years with an exercise price of $20.00 per share.

As of June 30, 2015 the Company has a long-term asset of $187,000 associated with the warrants received to purchase common stock of OncoSec. The Company reassesses the fair value of the warrants at each reporting date utilizing a Black-Scholes pricing model. Inputs used in the pricing model include estimates of OncoSec stock price volatility, expected warrant life and risk-free interest rate. The Company develops its estimates based on publicly available historical data and knowledge of OncoSec. The Company reassesses the fair value of the warrants at each reporting date. The assumptions used to estimate the fair values of the OncoSec common stock warrants at June 30, 2015 are presented below:



Risk-free interest rate	0.28-0.64%
Expected volatility	90%
Expected life in years	1.25-1.75
Dividend yield	—

As a result of these calculations, the Company recorded a decrease in fair value of the two warrants of $73,000 and $364,000 for the three and six months ended June 30, 2015, respectively, and a (decrease) increase in fair value of the two warrants of $(529,000) and $164,000 for the three and six months ended June 30, 2014, respectively. The change in fair value is reflected in the Company's condensed consolidated statements of operations as a component of change in fair value of common stock warrants.

The following table presents a summary of changes in fair value of the Company’s total Level 3 financial assets for the six months ended June 30, 2015:



Balance at January 1, 2015	$	550,000
Decrease in fair value included in change in fair value of common stock warrants	(363,500		)
Balance at June 30, 2015	$	186,500

Level 3 liabilities held as of June 30, 2015 consist of common stock warrant liabilities associated with warrants to purchase the Company's common stock issued in March 2013. If unexercised, the warrants will expire in September 2018. During the three and six months ended June 30, 2015, no warrants were exercised. During the three and six months ended June 30, 2014, warrants to purchase 170,455 and 2,071,475 shares of common stock were exercised, respectively.

As of June 30, 2015 the Company has a $1.7 million common stock warrant liability. The Company reassesses the fair value of the common stock warrants at each reporting date utilizing a Black-Scholes pricing model. Inputs used in the pricing model include estimates of stock price volatility, expected warrant life and risk-free interest rate. The Company develops its estimates based on historical data. The assumptions used to estimate the fair value of common stock warrants at June 30, 2015 are presented below:



Risk-free interest rate	1.01%
Expected volatility	81%
Expected life in years	3.25
Dividend yield	—

Changes in these assumptions as well as in the Company's stock price on the valuation date can have a significant impact on the fair value of the common stock warrant liability. As a result of these calculations, the Company recorded a decrease in fair value of $23,000 and $313,000 for the three and six months ended June 30, 2015, respectively, and a decrease in fair value of $1.4 million and $155,000 for the three and six months ended June 30, 2014, respectively. The change in fair value is reflected in the Company's condensed consolidated statements of operations as a component of change in fair value of common stock warrants. Warrants that were exercised during the period were revalued on the day prior to exercise and then reclassified into stockholders' equity upon exercise.

The following table presents the changes in fair value of the Company’s total Level 3 financial liabilities for the six months ended June 30, 2015:



Balance at January 1, 2015	$	2,022,729
Decrease in fair value included in change in fair value of common stock warrants	(312,500		)
Balance at June 30, 2015	$	1,710,229