Quarterly Financial Data - Quarterly Financial Data (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 27, 2014	Jun. 28, 2014	Mar. 29, 2014	Dec. 31, 2013	Sep. 28, 2013	Jun. 29, 2013	Mar. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$ 82,000	$ 86,000	$ 75,000	$ 389,000	$ 150,000	$ 229,000	$ 555,000	$ 776,000	$ 632,000	$ 1,710,000	$ 3,459,000
Loss from operations	3,234,000	3,116,000	3,158,000	2,799,000	2,499,000	3,370,000	2,380,000	2,233,000	(12,307,000)	(10,482,000)	(11,026,000)
Net loss	$ 2,849,000	$ 2,412,000	$ 55,000	$ 2,935,000	$ 3,875,000	$ 3,454,000	$ 2,436,000	$ 2,408,000	$ (8,251,000)	$ (12,173,000)	$ (10,928,000)
Basic and diluted loss per common share	$ (0.22)	$ (0.19)	$ 0.00	$ (0.25)	$ (0.34)	$ (0.42)	$ (0.54)	$ (0.58)	$ (0.64)	$ (1.71)	$ (3.34)
Weighted average number of shares outstanding	13,158,592	12,917,653	13,026,636	11,880,889	11,527,366	8,176,262	4,521,731	4,152,036