Organization and Business (Details)						1 Months Ended		3 Months Ended		9 Months Ended
		May. 13, 2015 USD ($) $ / shares shares	Oct. 27, 2014 shares	Jul. 01, 2013 shares	Jun. 11, 2013 shares	May. 31, 2015 $ / shares shares	Oct. 31, 2014	Sep. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) segment $ / shares shares	Sep. 30, 2014 USD ($)	May. 18, 2015 $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares		Oct. 26, 2014 shares
Organization and business
Number of segments | segment										1
General and administrative expense								$ 1,390,429	$ 1,455,605	$ 3,784,272	$ 3,196,120
Research and development expense								$ 1,239,831	$ 1,126,436	$ 4,414,162	3,275,991
Reverse Stock Split
Common stock, shares authorized | shares		50,000,000						50,000,000		50,000,000		50,000,000	15,000,000
Initial Public Offering
Net proceeds from initial public offering										$ 18,810,484
Common stock, shares authorized | shares		50,000,000						50,000,000		50,000,000		50,000,000	15,000,000
Preferred stock, shares authorized | shares		10,000,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.0001						$ 0.0001		$ 0.0001		$ 0.0001	$ 0.0001
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.0001
Deferred offering costs	[1]												$ 2,480,049
Liquidity
Accumulated deficit								$ (21,571,507)		$ (21,571,507)			$ (9,410,778)	[1]
IPO
Initial Public Offering
Underwriting discounts, commissions, and estimated offering expenses		$ 2,900,000
Underwriters' over-allotment option
Initial Public Offering
Underwriting discounts, commissions, and estimated offering expenses		1,200,000
Common Stock
Reverse Stock Split
Reverse stock split ratio			0.667				0.667
Common stock, shares authorized | shares			15,000,000												10,000,000
Initial Public Offering
Shares issued (in shares) | shares										2,860,000
Common stock, shares authorized | shares			15,000,000												10,000,000
Common Stock | IPO
Initial Public Offering
Shares issued (in shares) | shares						2,860,000
Shares issued (price per share) | $ / shares						$ 7.00
Net proceeds from initial public offering		$ 15,900,000
Underwriting discounts, commissions, and estimated offering expenses										$ 2,897,825
Issuance of common stock upon conversion (in shares) | shares		2,010,596
Common Stock | Underwriters' over-allotment option
Initial Public Offering
Underwriting discounts, commissions, and estimated offering expenses										1,209,802
Napo
Organization and business
Number of shares issued in exchange for cash and services | shares					2,666,666
Service Agreement
Organization and business
Research and development expense										$ 28,764
Service Agreement | Napo
Organization and business
Number of shares issued in exchange for cash and services | shares				2,666,666
General and administrative expense											$ 114,858
Series A redeemable convertible preferred stock
Initial Public Offering
Preferred shares outstanding | shares		0						0		0			3,015,902
Series A redeemable convertible preferred stock | IPO
Initial Public Offering
Shares automatically converted at closing of IPO (in shares) | shares		3,015,902

[1] The condensed balance sheet at December 31, 2014 is derived from the audited financial statements at that date included in the Company’s prospectus filed with the Securities and Exchange Commission pursuant to Rule 424(b)(4) on May 14, 2015.