Selling, general and administrative expenses (Tables)

6 Months Ended

Jun. 30, 2020

Selling General And Administrative Expenses [Abstract]

Schedule of Selling, General and Administrative Expenses

Selling, general and administrative expenses consist of the following:

	Three months ended June 30,				Six months ended June 30,
	2019		2020		2019		2020
Personnel expenses	$	148,910	$	154,517	$	291,390	$	304,145
Operational expenses		45,286		28,755		91,496		73,502
Depreciation and amortization		2,116		3,040		4,828		6,007
	$	196,312	$	186,312	$	387,714	$	383,654