Stock Award Plan - Summary of Stock Options Outstanding and Exercisable by Exercise Price (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options Outstanding, Number Outstanding	1,573,568
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	8 years 4 months 24 days
Options Outstanding, Weighted-Average Exercise Price	$ 1.78	$ 0.81
Options Vested and Exercisable, Number Vested and Exercisable	357,920
Options Vested and Exercisable, Weighted-Average Exercise Price	$ 1.42
Exercise Price 0.10
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise Price	$ 0.10
Options Outstanding, Number Outstanding	14,167
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	5 years 7 months 6 days
Options Outstanding, Weighted-Average Exercise Price	$ 0.10
Exercise Price 0.16
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise Price	$ 0.16
Options Outstanding, Number Outstanding	128,750
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	6 years 1 month 6 days
Options Outstanding, Weighted-Average Exercise Price	$ 0.16
Options Vested and Exercisable, Number Vested and Exercisable	72,333
Options Vested and Exercisable, Weighted-Average Exercise Price	$ 0.16
Exercise Price 0.37
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise Price	$ 0.37
Options Outstanding, Number Outstanding	317,584
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	7 years 4 months 24 days
Options Outstanding, Weighted-Average Exercise Price	$ 0.37
Options Vested and Exercisable, Number Vested and Exercisable	64,500
Options Vested and Exercisable, Weighted-Average Exercise Price	$ 0.37
Exercise Price 0.97
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise Price	$ 0.97
Options Outstanding, Number Outstanding	263,833
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	8 years 2 months 12 days
Options Outstanding, Weighted-Average Exercise Price	$ 0.97
Options Vested and Exercisable, Number Vested and Exercisable	68,828
Options Vested and Exercisable, Weighted-Average Exercise Price	$ 0.97
Exercise Price 2.51
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise Price	$ 2.51
Options Outstanding, Number Outstanding	269,401
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	8 years 8 months 12 days
Options Outstanding, Weighted-Average Exercise Price	$ 2.51
Options Vested and Exercisable, Number Vested and Exercisable	95,626
Options Vested and Exercisable, Weighted-Average Exercise Price	$ 2.51
Exercise Price 2.89
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise Price	$ 2.89
Options Outstanding, Number Outstanding	52,000
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 2 months 12 days
Options Outstanding, Weighted-Average Exercise Price	$ 2.89
Exercise Price 2.93
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise Price	$ 2.93
Options Outstanding, Number Outstanding	372,833
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 4 months 24 days
Options Outstanding, Weighted-Average Exercise Price	$ 2.93
Options Vested and Exercisable, Number Vested and Exercisable	49,133
Options Vested and Exercisable, Weighted-Average Exercise Price	$ 2.93
Exercise Price 3.18
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise Price	$ 3.18
Options Outstanding, Number Outstanding	155,000
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	9 years 7 months 6 days
Options Outstanding, Weighted-Average Exercise Price	$ 3.18
Options Vested and Exercisable, Number Vested and Exercisable	7,500
Options Vested and Exercisable, Weighted-Average Exercise Price	$ 3.18