Income Taxes - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		12 Months Ended
	May 31, 2013	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2018
Tax Credit Carryforward [Line Items]
Annual distribution of net taxable income for U.S. federal income tax not to apply to our earnings that we distribute (percent)		90.00%
Net taxable income subject to distribution (percent)		100.00%
Excise tax rate		4.00%
Income tax provision		$ 101,000	$ 120,000
Deferred tax assets		0	0
Deferred tax liabilities		$ 0	$ 0
U.S. federal corporate income tax rate		21.00%		35.00%
Common stock, shares issued	25,875,000	1,909,909	455
Net operating losses carried forward					$ 159,000,000
NOLs expiration date		Dec. 31, 2029
Open tax year		2015 2017 2018
Internal Revenue Service [Member]
Tax Credit Carryforward [Line Items]
Net operating losses limit per annum		$ 2,000,000
Net operating losses limitations		The availability of our NOLs is generally limited to $2.0 million per annum