Organization and Summary of Significant Accounting Policies - Additional Information 2 (Details) - USD ($)	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Accounting Policies [Abstract]
Shipping and handling costs	$ 621,400	$ 631,600

Cost incurred during the reporting period in transporting goods and services to customers. Includes freight-out costs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 45
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=68080631&loc=d3e61069-111654

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 45
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=68075638&loc=d3e60635-111653

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18726-107790

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 605
-SubTopic 45
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82851458&loc=d3e221937-122793

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