Inventories

9 Months Ended

Sep. 30, 2020

Inventories [Abstract]

Inventories

4. Inventories

Inventories as of December 31, 2019 and September 30, 2020 consisted of the following:

	December 31,		September 30,
	2019		2020
Raw materials	$	482,836	$	408,288
Work in progress		1,254,490		931,717
Finished goods		6,929,388		2,279,527
	$	8,666,714	$	3,619,532

During the three months ended September 30, 2019 and 2020, write-downs of inventories to lower of cost or net realizable value of nil and $267,117, respectively, were charged to cost of revenues.

During the nine months ended September 30, 2019 and 2020, write-downs of inventories to lower of cost or net realizable value of $557,668 and $724,156, respectively, were charged to cost of revenues.