Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - Recapitalization Transactions (Details)			1 Months Ended				6 Months Ended	12 Months Ended
	May 06, 2014 shares	Apr. 30, 2014 shares	Oct. 31, 2014 shares	Sep. 30, 2014 USD ($)	May 31, 2014 USD ($) shares	Jan. 31, 2014 shares	Oct. 31, 2014 shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares
Equity
Proceeds from issuance of common stock | $								$ 10,000,525	$ 42,122,004	$ 1,409
Noncash share-based compensation expense, nonemployees | $										2,063,565
Noncash share-based compensation expense, employees | $								$ 3,269,366	$ 1,600,625
General and Administrative | Existing Investors and Employees
Equity
Noncash share-based compensation expense, employees | $										$ 123,958
General and Administrative | New Investor
Equity
Noncash share-based compensation expense, nonemployees | $				$ 958,914	$ 792,000
Common stock
Equity
Issuance of common stock (in shares)					797,871			794,906	3,450,000	74,923
Number of shares forfeited										359,042
Number of shares issued as a result of conversion		1,046,847
Common stock | Existing Investors and Employees
Equity
Issuance of common stock (in shares)					74,923
Proceeds from issuance of common stock | $					$ 1,409
Common stock | New Investor
Equity
Issuance of common stock (in shares)					478,723
Number of shares forfeited			41,667
Common stock | Founder
Equity
Issuance of common stock (in shares)					319,148
Number of shares forfeited					359,042
Convertible preferred stock
Equity
Shares issued	720,002						6,244,051			6,244,051
Number of shares converted									6,964,053	(720,002)
Convertible preferred stock | Common stock
Equity
Conversion ratio	0.57434
Redeemable convertible preferred stock Series A
Equity
Number of shares converted		720,002								720,002
Redeemable convertible preferred stock Series B
Equity
Shares issued						200,002				250,000
Number of shares converted		1,248,109								1,248,109