Quarterly Results of Operation (Unaudited) - Summary of Unaudited Quarterly Results of Operations (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 3,398,000	$ 183,000	$ 1,584,000	$ 1,946,000	$ 53,000	$ 1,466,000			$ 7,111,000	$ 1,519,000
Cost of revenue	3,500,000	921,000	972,000	1,334,000	38,000	1,031,000			6,727,000	1,069,000
Amortization of intangible assets	2,714,000	1,821,000	1,687,000	1,636,000	1,655,000	1,709,000	$ 1,786,000	$ 1,817,000	7,858,000	6,967,000	$ 2,185,000
Goodwill impairment			0				61,784,000		0	61,784,000	0
Restructuring and other charges					(21,000)		3,085,000			3,064,000
Inventory write-down related to restructuring							2,565,000			2,565,000
Change in fair value of contingent consideration	800,000	773,000	(774,000)	1,227,000					2,026,000	482,000	(400,000)
Issuance costs for warrants			627,000						627,000
Other operating expenses	14,298,000	12,337,000	11,538,000	13,627,000	12,769,000	12,278,000	11,509,000	13,163,000	51,800,000	49,719,000
Change in fair value of warrant liabilities	58,521,000	22,887,000	2,326,000						83,734,000
Interest expense, net	684,000	695,000	662,000	394,000	420,000	462,000	394,000	578,000	2,435,000	1,854,000
Loss before income taxes	(77,119,000)	(39,251,000)	(15,454,000)	(16,272,000)	(14,808,000)	(14,014,000)	(81,123,000)	(15,558,000)	(148,096,000)	(125,503,000)	(47,972,000)
Income tax benefit	963,000	738,000	741,000	858,000	816,000	1,070,000	992,000	2,645,000	3,300,000	5,523,000	1,024,000
Net loss	$ (76,156,000)	$ (38,513,000)	$ (14,713,000)	$ (15,414,000)	$ (13,992,000)	$ (12,944,000)	$ (80,131,000)	$ (12,913,000)	$ (144,796,000)	$ (119,980,000)	$ (46,948,000)
Net loss per share - basic and diluted	$ (0.40)	$ (0.26)	$ (0.11)	$ (0.13)	$ (0.12)	$ (0.11)	$ (0.70)	$ (0.12)	$ (0.97)	$ (1.07)	$ (0.59)