Convertible Notes (Details) - USD ($)								12 Months Ended
	Feb. 10, 2016	Aug. 12, 2014	Aug. 11, 2014	Jun. 20, 2014	Jun. 19, 2014	Mar. 07, 2014	Jan. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Convertible Notes
Proceeds from convertible notes										$ 1,000,000
Net Proceeds from Initial Public Offering								$ 246,489,901
Class B-1 Preferred Stock
Convertible Notes
Shares issued (in shares)									1,011,721	809,385
Shares converted (in shares)	3,278,938
Class B-2 Preferred Stock
Convertible Notes
Shares converted (in shares)	326,557
Class C Preferred Stock
Convertible Notes
Shares issued (in shares)									1,102,945	1,135,084
Shares converted (in shares)	2,365,020
PBM Capital Investments, LLC | Preferred Stock | Class B-1 Preferred Stock
Convertible Notes
Nonemployee stock option, exercise price (in dollars per share)							$ 2.47
Shares issued (in shares)						1,011,721	1,011,721
Share price (in dollars per share)						$ 2.47
PBM Capital Investments, LLC | Preferred Stock | Class B-2 Preferred Stock
Convertible Notes
Warrant to purchase shares, number (in shares)							163,278
PBM Capital Investments, LLC | Preferred Stock | Class B-2 Preferred Stock | Class B-2 Warrant
Convertible Notes
Warrant to purchase shares, number (in shares)						130,623	130,623
Warrants, exercise price (in dollars per share)						$ 2.57	$ 2.57
Deerfield Private Design Fund III | Preferred Stock | Class C Preferred Stock
Convertible Notes
Conversion price (in dollars per share)				$ 3.96
Shares issued (in shares)		551,472	504,478
Share price (in dollars per share)		$ 4.53	$ 3.96
Class B Note | Class B-1 Preferred Stock
Convertible Notes
Shares issued in conversion										202,345
Class B Note | PBM Capital Investments, LLC
Convertible Notes
Face amount							$ 500,000
Interest rate (as a percent)							8.00%
Minimum amount benchmark from issuance or sale of equity securities to be considered for conversion of debt							$ 500,000
Proceeds from convertible notes							500,000
Fair value of nonemployee stock option							$ 112,835
Nonemployee stock option, exercise price (in dollars per share)							$ 2.47
Nonemployee stock option, volatility rate (as a percent)							45.00%
Nonemployee stock option, expected term (in months)							1 month
Nonemployee stock option, dividend yield (as a percent)							0.00%
Nonemployee stock option, interest rate (as a percent)							0.40%
Class B Note | PBM Capital Investments, LLC | Interest expense
Convertible Notes
Unamortized debt discount										$ 112,835
Class B Note | PBM Capital Investments, LLC | Class B-1 Preferred Stock
Convertible Notes
Shares converted (in shares)	3,278,938
Class B Note | PBM Capital Investments, LLC | Class B-2 Preferred Stock
Convertible Notes
Shares converted (in shares)	326,557
Class B Note | PBM Capital Investments, LLC | Preferred Stock | Class B-1 Preferred Stock
Convertible Notes
Conversion price (in dollars per share)						$ 2.47	$ 2.47
Fair value of contingent milestone shares							$ 0
Contingent milestone shares, exercise price (in dollars per share)							$ 2.40
Unamortized debt discount							$ 112,835
Share price (in dollars per share)							$ 2.47
Shares issued in conversion						202,345
Class B Note | PBM Capital Investments, LLC | Preferred Stock | Class B-2 Preferred Stock | Class B-2 Warrant
Convertible Notes
Warrant to purchase shares, number (in shares)						32,652
Warrants, exercise price (in dollars per share)						$ 2.57
Deerfield Convertible Note | Class C Preferred Stock
Convertible Notes
Shares issued in conversion										126,991
Deerfield Convertible Note | Deerfield Private Design Fund III
Convertible Notes
Face amount					$ 500,000
Interest rate (as a percent)					5.00%
Origination fee (as a percent)					2.50%
Fair value of debt					$ 500,000
Deerfield Convertible Note | Deerfield Private Design Fund III | Class C Preferred Stock
Convertible Notes
Shares converted (in shares)	2,365,020
Deerfield Convertible Note | Deerfield Private Design Fund III | Preferred Stock | Class C Preferred Stock
Convertible Notes
Conversion price (in dollars per share)			$ 3.96
Shares issued in conversion			126,991	126,991
IPO | Common Stock
Convertible Notes
Shares issued (in shares)	4,750,000							5,277,941
Share price (in dollars per share)	$ 20.00
Net Proceeds from Initial Public Offering	$ 88,350,000
Shares converted (in shares)								8,695,640
IPO | Class B Note | PBM Capital Investments, LLC | Common Stock
Convertible Notes
Shares issued (in shares)	4,750,000
Share price (in dollars per share)	$ 20.00
Net Proceeds from Initial Public Offering	$ 88,350,000
IPO | Deerfield Convertible Note | Deerfield Private Design Fund III | Common Stock
Convertible Notes
Shares issued (in shares)	4,750,000
Share price (in dollars per share)	$ 20.00
Net Proceeds from Initial Public Offering	$ 88,350,000