CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Net sales	$ 293,931,961	$ 244,166,312
Cost of sales	(237,056,725)	(196,792,444)
Gross profit	56,875,236	47,373,868
Research and development expenses	(13,492,057)	(9,512,074)
Selling and distribution expenses	(10,087,885)	(7,500,560)
General and administrative expenses	(19,300,316)	(15,393,791)
Foreign currency transaction gain (loss)	1,860,323	(2,390,417)
Total operating expenses	(41,019,935)	(34,796,842)
Income from operations	15,855,301	12,577,026
Changes in fair value of warrant liability	0	259
Changes in fair value of foreign exchange derivatives	(1,145,387)	273,496
Government grants	2,460,013	1,357,852
Other income	268,438	458,247
Equity in (loss) earnings of investee	(140,132)	107,243
Gain on dilution in equity method investee	0	500,270
Gain on sale of long-term investment	0	1,677,367
Gain on deconsolidation of a subsidiary	0	6,004,008
Interest expenses	(1,761,718)	(1,426,547)
Income before income taxes	15,536,515	21,529,221
Income taxes expenses	(2,381,934)	(4,315,325)
Net income	13,154,581	17,213,896
Less: net income attributable to non-controlling interest	0	441,044
Net income attributable to the Company	13,154,581	16,772,852
Comprehensive income
Net income	13,154,581	17,213,896
Foreign currency translation (loss) gain	(4,264,330)	4,234,078
Comprehensive income	8,890,251	21,447,974
Less: comprehensive income attributable to non-controlling interest	0	479,098
Comprehensive income attributable to the Company	$ 8,890,251	$ 20,968,876
Earnings per share of common stock attributable to the Company
- Basic	$ 0.85	$ 1.09
- Diluted	$ 0.84	$ 1.09
Weighted average number of common stock outstanding
- Basic	15,546,644	15,326,797
- Diluted	15,606,177	15,435,371