Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Schedule of fair value of financial assets and liabilities measured at fair value and classification by level of input

The Company measures the fair value of financial assets and liabilities using the highest level of inputs that are reasonably available as of the measurement date. The following tables summarize the fair value of financial assets (marketable securities) that are measured at fair value, and the classification by level of input within the fair value hierarchy:

	Fair Value Measurements as of December 31, 2017
Investments:	Level 1		Level 2		Level 3		Total
Money market funds	$	101	$	—	$	—	$	101
Total assets measured at fair value	$	101	$	—		—	$	101

	Fair Value Measurements as of December 31, 2016
	Level 1		Level 2		Level 3		Total
Investments:
Money market funds	$	101	$	—	$	—	$	101
Total assets measured at fair value	$	101	$	—		—	$	101

Schedule of antidilutive securities excluded from computations of diluted net loss per common share

The following shares subject to outstanding potentially dilutive securities have been excluded from the computations of diluted net loss per common share as the effect of including such securities would be antidilutive:

	Year Ended December 31,
	2017		2016
Options to purchase common stock		2,448,383		1,835,835
Warrants to purchase common stock		331,193		356,193
		2,779,576		2,192,028