Stockholders Deficit - Additional Information (Details) - USD ($)					1 Months Ended				3 Months Ended	6 Months Ended				12 Months Ended
	Jan. 01, 2019	Jan. 31, 2018	Jun. 30, 2017	Apr. 30, 2017	Jun. 30, 2018	Jan. 31, 2018	Jan. 31, 2017	Feb. 28, 2014	Mar. 31, 2018	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2016	May 11, 2015
Class Of Stock [Line Items]
Issuance of common stock from the ATM Offering, Shares									5,733,314
Gross proceeds from issuance of common stock									$ 21,100,000
Sales commission									600,000
Other offering expenses paid									200,000
Net proceeds from issuance of common stock									$ 20,200,000
Common stock, shares authorized										200,000,000		200,000,000		200,000,000	200,000,000
Common stock, par value										$ 0.001		$ 0.001		$ 0.001	$ 0.001
Common stock, shares issued										28,585,449		13,929,763		28,585,449	13,929,763
Common stock, shares outstanding										28,585,449		13,929,763		28,585,449	13,929,763
Common stock, voting rights														Each share of common stock is entitled to one vote.
Common stock, conversion features														The shares of common stock have no preemptive or conversion rights, no redemption or sinking fund provisions, no liability for further call or assessment, and are not entitled to cumulative voting rights.
Additional treasury stock														0	0
Preferred stock, shares authorized										10,000,000				10,000,000
Preferred stock, par value										$ 0.001				$ 0.001
Share based compensation arrangement by share based payment award, options, grants in period, weighted average grant date fair value														$ 2.29	$ 1.14
Accelerated vesting of stock options					46,613
Options extended exercise period					1 year
Incremental stock-based compensation expense														$ 79,400
Maximum aggregate number of common stock available purchase under employee stock purchase plan																250,000
Maximum number of shares that may be purchased by eligible participants under employee stock purchase plan																7,500
Stock issued under employee stock purchase plans														2,304	61,141
Two Thousand Fourteen Equity Incentive Plan
Class Of Stock [Line Items]
Shares reserved for issuance																		940,112
Number of shares available for issuance										0				0
Options granted in term														10 years
Two Thousand Fourteen Equity Incentive Plan | Subsequent Event
Class Of Stock [Line Items]
Number of additional shares registered for issuance	1,143,417
Stock-based Compensation | 2011 Equity Incentive Plan
Class Of Stock [Line Items]
Percentage of increase on outstanding shares								20.00%
Number of Shares, Granted								0
Employee Stock Option
Class Of Stock [Line Items]
Number of Shares, Granted														802,500	494,500
Unrecognized compensation expense										$ 1,675,285				$ 1,675,285
Compensation expense period expected to be recognized														3 years 14 days
Options to purchase common stock outstanding										2,047,237		1,517,771		2,047,237	1,517,771		1,161,705
Employee Stock Option | 2011 Equity Incentive Plan
Class Of Stock [Line Items]
Shares reserved for issuance																		14,006
Restricted Stock Units R S U
Class Of Stock [Line Items]
Share based compensation arrangement by share based payment award, options, grants in period, weighted average grant date fair value														$ 3.63	$ 1.75
Unrecognized compensation expense										$ 701,780				$ 701,780
Compensation expense period expected to be recognized														3 years 3 months 18 days
Vested and unissued RSU awards, description														Vested and unissued awards at December 31, 2018 represents RSU awards granted on August 16, 2018 for which the second vesting date was December 31, 2018, but for which issuance of awards occurred on the next business day, January 2, 2019.
Vested and unissued RSU awards granted date														Aug. 16, 2018
Vested and unissued RSU awards vesting date														Dec. 31, 2018
Vested and unissued RSU awards issuance date														Jan. 02, 2019
Board Of Directors
Class Of Stock [Line Items]
Retirement of treasury stock, shares							1,396
Board Of Directors | Two Thousand Fourteen Equity Incentive Plan | Minimum
Class Of Stock [Line Items]
Options exercise period														1 year
Board Of Directors | Two Thousand Fourteen Equity Incentive Plan | Maximum
Class Of Stock [Line Items]
Options exercise period														4 years
Underwritten Public Offering
Class Of Stock [Line Items]
Common stock price per share		$ 2.90				$ 2.90
Issuance of common stock from the ATM Offering, Shares						13,915,000
Net proceeds from initial public offering after underwriters' discounts, commissions and offering expenses						$ 37,700,000
Over-Allotment Option
Class Of Stock [Line Items]
Issuance of common stock from the ATM Offering, Shares						1,815,000
2014 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Percentage of increase on outstanding shares														1.00%
Shares reserved for issuance										158,067				158,067
Vested and unissued RSU awards, description														The number of shares of common stock reserved for issuance automatically increases on January 1 of each calendar year, from January 1, 2016 to January 1, 2024 by the least of (i) 1% of the total number of shares of the Company’s common stock outstanding on December 31 of the preceding calendar year, (ii) 195,000 shares, or (iii) a number determined by the Company’s board of directors that is less than (i) and (ii).
Maximum aggregate number of common stock available purchase under employee stock purchase plan										110,820				110,820
Common stock issuance offering date														Jan. 01, 2016
Common stock issuance expiration date														Jan. 01, 2024
Options to purchase common stock outstanding										195,000				195,000
Maximum contribution eligible compensation during a period to purchase common stock										15.00%				15.00%
Fair market value of company common stock, shares offering price														85.00%
Fair market value of company common stock, shares purchase price														85.00%
Common stock shares issued										35,805	4,176	39,969	39,972	39,993
Weighted average price per share			$ 1.79		$ 2.81					$ 1.57	$ 2.81	$ 1.61	$ 1.79	$ 1.57	$ 1.61
2014 Employee Stock Purchase Plan | Subsequent Event
Class Of Stock [Line Items]
Number of additional shares registered for issuance	195,000
Employee Stock Purchase Plan
Class Of Stock [Line Items]
Net proceeds from issuance of common stock														$ 9,997	$ 130,649
Common Stock
Class Of Stock [Line Items]
Issuance of common stock from the ATM Offering, Shares									300,000
Gross proceeds from issuance of common stock									$ 600,000
Stock issued under employee stock purchase plans														82,261	141,082
Sales Agreement
Class Of Stock [Line Items]
Common stock price per share				$ 0.001
Common stock aggregate offering price		$ 23,000,000	$ 40,000,000	$ 20,000,000