Business and Basis of Presentation (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Organization And Basis Of Presentation [Line Items]
Restructuring Charges	$ 2,300,000	$ 2,300,000
Revenues				$ 5,477,618	$ 8,694,558
Accounts receivable, net	726,670	726,670		726,670		$ 1,082,957
Net proceeds from issuance of stock and warrants				7,497	0
Accumulated deficit	192,328,275	192,328,275		192,328,275		191,016,591
Cash and cash equivalents	4,958,058	4,958,058		4,958,058		6,780,429
Allowance for doubtful accounts	25,000	25,000		25,000		25,000
Prepaid expenses and other current assets	(1,101,154)	(1,101,154)		(1,101,154)		(860,915)
Assets, Current	(8,849,313)	(8,849,313)		(8,849,313)		(11,586,165)
Accrued Sales Return provisions	741,607	741,607		741,607		1,101,658
Liabilities, Current	(4,839,893)	(4,839,893)		(4,839,893)		(6,592,897)
Operating Lease, Liability, Noncurrent	(1,116,734)	(1,116,734)	$ (1,116,734)	(1,116,734)	(1,116,734)	(1,301,172)
Stockholders' Equity Attributable to Parent	4,857,650	4,857,650	7,721,608	4,857,650	7,721,608	6,097,811	$ 5,017,389
Cost of revenues		3,143,787	1,950,304	5,468,018	4,905,564
Gross Profit		(789,104)	1,801,264	9,600	3,788,994
Net Income (Loss) Available to Common Stockholders, Diluted		(3,362,191)	$ 573,928	(1,311,684)	$ 1,740,180
Compensation cost not yet recognized	139,588	$ 139,588		$ 139,588
Compensation cost not yet recognized, period for recognition				1 year 3 months 23 days
Earnings Per Share, Basic		$ (0.37)	$ 0.08	$ (0.16)	$ 0.25
Earnings Per Share, Diluted		$ (0.37)	$ 0.04	$ (0.16)	$ 0.13
Operating Lease, Right-of-Use Asset	(1,645,668)	$ (1,645,668)		$ (1,645,668)		(1,968,062)
Other long-term assets	(29,824)	(29,824)		(29,824)		(30,314)
Assets	(10,814,277)	(10,814,277)		(10,814,277)		(13,991,880)
Accrued Liabilities, Current	(3,081,192)	(3,081,192)		(3,081,192)		(2,236,633)
Liabilities	(5,956,627)	(5,956,627)		(5,956,627)		$ (7,894,069)
Collaboration Income		$ 1,381,818	$ 3,749,999	$ 7,116,667	$ 8,505,704
One Customer [Member] | Revenue | Customer Concentration Risk
Organization And Basis Of Presentation [Line Items]
Concentration risk, percentage				20.00%
Two Customers | Revenue | Customer Concentration Risk
Organization And Basis Of Presentation [Line Items]
Concentration risk, percentage		31.00%	24.00%		29.00%
Two Customers | Accounts Receivable | Customer Concentration Risk
Organization And Basis Of Presentation [Line Items]
Concentration risk, percentage						45.00%
Three Customers [Member] | Accounts Receivable | Customer Concentration Risk
Organization And Basis Of Presentation [Line Items]
Concentration risk, percentage				62.00%
CalculatedUnderRevenueGuidanceInEffectBeforeTopic842 [Member]
Organization And Basis Of Presentation [Line Items]
Prepaid expenses and other current assets	(1,128,049)	$ (1,128,049)		$ (1,128,049)		$ (905,767)
Assets, Current	(8,876,208)	(8,876,208)		(8,876,208)		(11,631,017)
Liabilities, Current	(4,381,954)	(4,381,954)		(4,381,954)		(6,015,437)
Operating Lease, Liability, Noncurrent	0	0		0		0
Operating Lease, Right-of-Use Asset	0	0		0		0
Other long-term assets	(73,924)	(73,924)		(73,924)		(74,892)
Assets	(9,239,604)	(9,239,604)		(9,239,604)		(12,113,248)
Accrued Liabilities, Current	(2,623,253)	(2,623,253)		(2,623,253)		(1,659,173)
Liabilities	(4,381,954)	(4,381,954)		(4,381,954)		(6,015,437)
DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic842 [Member]
Organization And Basis Of Presentation [Line Items]
Prepaid expenses and other current assets	26,895	26,895		26,895		44,852
Assets, Current	26,895	26,895		26,895		44,852
Liabilities, Current	(457,939)	(457,939)		(457,939)		(577,460)
Operating Lease, Liability, Noncurrent	(1,116,734)	(1,116,734)		(1,116,734)		(1,301,172)
Operating Lease, Right-of-Use Asset	(1,645,668)	(1,645,668)		(1,645,668)		(1,968,062)
Other long-term assets	44,100	44,100		44,100		44,578
Assets	(1,574,673)	(1,574,673)		(1,574,673)		(1,878,632)
Accrued Liabilities, Current	(457,939)	(457,939)		(457,939)		(577,460)
Liabilities	$ (1,574,673)	$ (1,574,673)		$ (1,574,673)		$ (1,878,632)