Summary of Significant Accounting Policies - Net Loss Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Antidilutive Common Stock Equivalents Excluded from Computation of Diluted Net Loss Per Share
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	2,112,008	1,593,606	2,112,008	1,593,606
Options to purchase Common stock
Antidilutive Common Stock Equivalents Excluded from Computation of Diluted Net Loss Per Share
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	2,087,442	1,534,201	2,087,442	1,534,201
Warrants for the purchase of Common Stock
Antidilutive Common Stock Equivalents Excluded from Computation of Diluted Net Loss Per Share
Anti-dilutive securities excluded from the calculation of diluted net loss per share (in shares)	24,566	59,405	24,566	59,405