Stockholder's Equity

6 Months Ended

Jun. 30, 2016

Equity [Abstract]

Stockholder's Equity

Stockholder's Equity

Authorized, Issued, and Outstanding Common Stock

The Company’s common stock has a par value of $0.001 per share and consists of 125,000,000 authorized shares as of June 30, 2016, and December 31, 2015; 23,424,741 and 13,905,599 shares were issued and outstanding at June 30, 2016, and December 31, 2015, respectively. The following table summarizes common stock share activity for the six months ended June 30, 2016:

	Shares of Common Stock	Common Stock		Additional Paid-in Capital		Accumulated Deficit			Total Stockholders' Equity
Balance, December 31, 2015	13,905,599	$	14	$	192,069	$	(150,134	)	$	41,949
Net loss	—	—		—		(15,312		)	(15,312		)
Stock-based compensation expense	—	—		616		—			616
Common stock issued through employee stock purchase plan	1,229	—		5		—			5
Common stock issued through Sales Agreement	142,913	—		558		—			558
Common stock issued for cash under public offering, net of expenses	9,375,000	9		16,050		—			16,059
Balance, June 30, 2016	23,424,741	$	23	$	209,298	$	(165,446	)	$	43,875

Shares Reserved for Future Issuance

The Company had reserved shares of common stock for future issuance as follows:

	June 30, 2016	December 31, 2015
Outstanding stock options	1,804,473	1,379,727
Outstanding Series C-1 Preferred warrants	14,033	14,033
Outstanding 2016 Public Offering warrants	4,218,750	—
For possible future issuance under 2014 Equity Incentive Plan (Note 9)	683,892	552,415
For possible future issuance under Employee Stock Purchase Plan (Note 9)	78,465	50,283
For possible future issuance under 2015 Inducement Plan (Note 9)	165,000	165,000
Total common shares reserved for future issuance	6,964,613	2,161,458

Warrants Associated with Convertible Preferred Stock Issuances

In July 2006, the Company issued warrants to purchase 196,923 shares of Series C-1 Preferred Stock, which converted into the right to purchase 14,033 shares of common stock in connection with the Company's IPO; however, the Company refers to these warrants as its Series C-1 Preferred warrants. The Series C-1 Preferred warrants were issued in conjunction with a loan financing agreement with an original exercise price of $3.25 per share of Series C-1 Preferred, which converted into an exercise price of $45.61 per share of common stock in connection with the Company's IPO. These warrants remain outstanding as of March 31, 2016 and will expire on May 7, 2019, which is the five year anniversary of the Company's IPO. The fair value at the date of grant for these instruments was $459, which was recorded as a debt discount. The debt discount related to these warrants was fully amortized as of December 31, 2010. The Company determined that the warrants should be recorded as a derivative liability and stated at fair value at each reporting period. As of June 30, 2016 and December 31, 2015, the fair value of the warrant derivative liability was zero.

Warrants Associated with June 2016 Public Offering

On June 21, 2016, the Company completed the June 2016 Public Offering of its common stock and warrants pursuant to the Company's effective Shelf Registration (see Note 1). Each purchaser received a warrant to purchase 0.45 of a share for each share purchased in the June 2016 Public Offering. There is not expected to be any trading market for the warrants. Each warrant was exercisable immediately upon issuance, will expire five years from the date of issuance, and has an exercise price of $3.00 per share.

The warrants contain a provision where the warrant holder has the option to receive cash, equal to the Black-Scholes fair value of the remaining unexercised portion of the warrant, as cash settlement in the event that there is a fundamental transaction (contractually defined to include various merger, acquisition or stock transfer activities). Due to this provision, ASC 480, Distinguishing Liabilities from Equity requires that these warrants be classified as liabilities. The fair values of these warrants have been determined using the Black-Scholes valuation model, and the changes in the fair value are recorded in the accompanying statements of operations. During the three months ended June 30, 2016, the Company recorded a gain of $101 due to the change in fair value of the warrant liability. As of June 30, 2016, the fair value of the warrant liability was $4,594.