Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2017

Assets and Liabilities Measured at Fair Value on Recurring Basis



			Fair Value Measurements at December 31, 2016 Using
	December 31, 2016		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	833,831	$	833,831	$	—	$	—
Total	$	833,831	$	833,831	$	—	$	—

Liabilities:
Common stock warrants	$	4,641	$	—	$	—	$	4,641
Total	$	4,641	$	—	$	—	$	4,641



			Fair Value Measurements at September 30, 2017 Using
	September 30, 2017		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	$	197,370	$	197,370	$	—	$	—
Total	$	197,370	$	197,370	$	—	$	—

Summary of Changes in Fair Value of Company's Level 3 Financial Liabilities

The following table provides a summary of changes in the fair value of the Company’s Level 3 financial liabilities, which relate to warrants issued by the Company in offerings in 2013 and 2014, between December 31, 2016 and September 30, 2017.



	2014 Offering			2013 Offering			Total
Balance at December 31, 2016	$	4,112		$	529		$	4,641
Change in fair value of warrant liability from repricing (see Note 9)	177,999			66,612			244,611
Change in fair value of warrant liability	(147,278		)	(61,202		)	(208,480		)
Repurchase and retirement of warrants (see Note 9)	(34,833		)	(5,939		)	(40,772		)
Balance at September 30, 2017	$	—		$	—		$	—

Black-Scholes Inputs to Warrant Liability Valuation



	Black-Scholes Inputs to Warrant Liability Valuation at December 31, 2016
Warrants:	Stock Price		Exercise Price		Expected Volatility		Risk-Free Interest		Expected Term	Dividends
2014 Offering	$	5.92	$	65.28	64.19	%	1.33	%	2 years, 6 months	none
2013 Offering	$	5.92	$	64.00	71.61	%	0.99	%	1 year, 5 months	none