Shareholders' Equity - Summary of Stock Option Activity (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward
Number of Shares, Beginning Balance	1,544,826
Granted, Number of Shares	564,900
Forfeited, Number of Shares	(1,500)
Expired, Number of Shares	(168,448)
Number of Shares, Ending Balance	1,939,778	1,544,826
Vested and expected to vest, Number of Shares, Ending Balance	1,631,708
Exercisable, Number of Shares, Ending Balance	467,687
Weighted Average Exercise Price, Beginning Balance	$ 2.74
Granted, Weighted Average Exercise Price	1.02
Forfeited, Weighted Average Exercise Price	4.02
Expired, Weighted Average Exercise Price	4.79
Weighted Average Exercise Price, Ending Balance	2.06	$ 2.74
Vested and expected to vest, Weighted Average Exercise Price, Ending Balance	2.19
Exercisable, Weighted Average Exercise Price, Ending Balance	$ 3.88
Weighted Average Remaining Contractual Life (in years)	8 years 7 months 13 days	7 years 5 months 19 days
Vested and expected to vest, Weighted Average Remaining Contractual Life (in years)	8 years 5 months 15 days
Exercisable, Weighted Average Remaining Contractual Life (in years)	6 years 1 month 20 days
Balance outstanding, Aggregate Intrinsic Value		$ 46,582