Income Taxes - Additional Information (Detail) - USD ($)			12 Months Ended
	Apr. 01, 2020	Apr. 01, 2017	Dec. 31, 2018	Dec. 31, 2017
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)			$ (474,391)	$ 0
Federal net operating loss carryforwards			14,210,000	6,800,000
State net operating loss carryforwards			14,155,000	$ 6,700,000
Foreign net operating loss carryforwards			$ 94,100,000
Income tax operating loss carryforward expiration date			2036	2036
Deferred tax assets, tax credit carryforwards, orphan drug and research and development			$ 1,133,656	$ 697,406
Deferred tax assets, tax credit carryforwards, expiration year			2036
Provision for valuation allowance			$ 0
Foreign currency translation, tax			$ 474,391	$ 0
Foreign tax rate differential			17.00%
Foreign tax rate differential		19.00%	0.21%	2.17%
Effective income tax rate reconciliation, at federal statutory Income tax rate, percent			19.00%	19.25%
Decrease in the prior years deferred tax assets			$ 994,000
Federal [Member]
Income Taxes Disclosure [Line Items]
Deferred tax assets, tax credit carryforwards, orphan drug and research and development			$ 1,133,656	$ 697,406
Effective income tax rate reconciliation, at federal statutory Income tax rate, percent			21.00%	34.00%
Scenario, Forecast [Member]
Income Taxes Disclosure [Line Items]
Foreign tax rate differential	17.00%
Foreign tax rate differential	18.00%