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Change in Method of Accounting for Patent Costs - Schedule of Adjusted Comparative Consolidated Financial Statements (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2015	Jun. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Consolidated Statement of Operations
Selling, general and administrative	$ 25,838			$ 31,618	$ 1,826	$ 724	$ 1,079	$ 992					$ 227,678	$ 4,621	$ 2,423
Net loss	$ (26,822)			$ (32,849)	$ (2,755)	$ (918)	$ (1,423)	$ (1,089)	$ (117,470)	$ (2,512)	$ (160,110)	$ (3,430)	$ (236,876)	$ (6,185)	$ (2,047)
Earnings per share - basic and diluted	$ (0.33)			$ (0.54)	$ (0.09)	$ (0.11)	$ (0.19)	$ (0.38)					$ (3.31)	$ (0.75)	$ (2.57)
Consolidated Statement of Cash Flows
Net loss	$ (26,822)			$ (32,849)	$ (2,755)	$ (918)	$ (1,423)	$ (1,089)	(117,470)	(2,512)	(160,110)	(3,430)	$ (236,876)	$ (6,185)	$ (2,047)
Depreciation and amortization				26				31	986	63	981	79	1,472	36	4
Net cash used in operating activities				(7,372)				(38)	(10,162)	(2,091)	(14,361)	(2,844)	(25,305)	(5,418)	(668)
Investment in intangible assets									(483)			(7)
Net cash used in investing activities				(1,856)				2	(2,453)	(17)	(3,104)	(205)	(175,224)	(235)	(3)
Previously Reported
Consolidated Balance Sheet
Intangible assets, net	8,175			8,028	835	843	821	794		821		843	8,175	835	863
Accumulated deficit	(249,493)	$ (172,723)	$ (130,004)	(45,566)	(12,741)	(9,978)	(9,082)	(7,686)	(130,004)	(9,082)	(172,723)	(9,978)	(249,493)	(12,741)	(6,528)
Consolidated Statement of Operations
Selling, general and administrative		38,854	82,429	31,594	1,834	702	1,052	1,061	114,023		152,847		227,627	4,649	2,235
Net loss		$ (42,649)	$ (84,581)	$ (32,825)	$ (2,763)	$ (896)	$ (1,396)	$ (1,158)	$ (117,406)	(2,554)	$ (160,055)	(3,450)	$ (236,825)	$ (6,213)	$ (1,859)
Earnings per share - basic and diluted		$ (0.55)	$ (1.29)	$ (0.54)	$ (0.09)	$ (0.11)	$ (0.19)	$ (0.40)	$ (1.85)		$ (2.34)		$ (3.31)	$ (0.75)	$ (2.33)
Consolidated Statement of Cash Flows
Net loss		$ (42,649)	$ (84,581)	$ (32,825)	$ (2,763)	$ (896)	$ (1,396)	$ (1,158)	$ (117,406)	(2,554)	$ (160,055)	(3,450)	$ (236,825)	$ (6,213)	$ (1,859)
Depreciation and amortization				53				47	1,042	103	1,067	145	1,587	128	76
Net cash used in operating activities				(7,321)				(91)	(10,042)	(2,093)	(14,220)	(2,798)	(25,139)	(5,354)	(408)
Investment in intangible assets				(51)					(603)		(141)	(53)	(166)	(64)	(260)
Net cash used in investing activities				(1,907)				2	(2,573)	(17)	(3,245)	(251)	(175,390)	(299)	(263)
Effect of Change
Consolidated Balance Sheet
Intangible assets, net	(883)			(856)	(832)	(840)	(818)	(791)		(818)		(840)	(883)	(832)	(860)
Accumulated deficit	(883)			(856)	(832)	(840)	(818)	(791)		(818)		(840)	(883)	(832)	(860)
Consolidated Statement of Operations
Selling, general and administrative	(4)			24	(8)	22	27	(69)					51	(28)	188
Net loss	$ 4			$ (24)	$ 8	$ (22)	$ (27)	$ 69	(64)	42	(55)	20	$ (51)	$ 28	$ (188)
Earnings per share - basic and diluted	$ 0.00			$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.02					$ 0.00	$ 0.00	$ (0.24)
Consolidated Statement of Cash Flows
Net loss	$ 4			$ (24)	$ 8	$ (22)	$ (27)	$ 69	(64)	42	(55)	20	$ (51)	$ 28	$ (188)
Depreciation and amortization				(27)				(16)	(56)	(40)	(86)	(66)	(115)	(92)	(72)
Net cash used in operating activities				(51)				53	(120)	2	(141)	(46)	(166)	(64)	(260)
Investment in intangible assets				51					120		141	46	166	64	260
Net cash used in investing activities				51					120		141	46	166	64	260
As Adjusted
Consolidated Balance Sheet
Intangible assets, net	7,292	(888)	(896)	7,172	3	3	3	3	(896)	3	(888)	3	7,292	3	3
Accumulated deficit	(250,376)	(888)	(896)	(46,422)	$ (13,573)	$ (10,818)	$ (9,900)	$ (8,477)	(896)	$ (9,900)	(888)	$ (10,818)	(250,376)	(13,573)	(7,388)
Consolidated Statement of Operations
Selling, general and administrative		(9)	40										227,678	4,621	2,423
Net loss	$ (26,822)	$ 9	$ (40)	$ (32,849)									$ (236,876)	$ (6,185)	$ (2,047)
Earnings per share - basic and diluted	$ (0.33)	$ 0.00	$ 0.00	$ (0.54)									$ (3.31)	$ (0.75)	$ (2.57)
Consolidated Statement of Cash Flows
Net loss	$ (26,822)	$ 9	$ (40)	$ (32,849)									$ (236,876)	$ (6,185)	$ (2,047)
Depreciation and amortization													1,472	36	4
Net cash used in operating activities													(25,305)	(5,418)	(668)
Net cash used in investing activities													$ (175,224)	$ (235)	$ (3)
As Restated
Consolidated Balance Sheet
Intangible assets, net		7,164	7,620						7,620		7,164
Accumulated deficit		(222,667)	(176,276)						(176,276)		(222,667)
Consolidated Statement of Operations
Selling, general and administrative		41,819	128,372						159,966		201,755
Net loss		$ (46,321)	$ (130,853)						$ (163,678)		$ (209,999)
Earnings per share - basic and diluted		$ (0.60)	$ (1.99)						$ (2.58)		$ (3.07)
Consolidated Statement of Cash Flows
Net loss		$ (46,321)	$ (130,853)						$ (163,678)		$ (209,999)
As Restated and Adjusted
Consolidated Balance Sheet
Intangible assets, net		6,276	(6,724)						(6,724)		6,276
Accumulated deficit		223,555	(177,172)						$ (177,172)		$ 223,555
Consolidated Statement of Operations
Selling, general and administrative		41,810	128,412
Net loss		$ (46,312)	$ (130,893)
Earnings per share - basic and diluted		$ (0.60)	$ (1.99)
Consolidated Statement of Cash Flows
Net loss		$ (46,312)	$ (130,893)
As Computed
Consolidated Statement of Operations
Selling, general and administrative	25,842
Net loss	$ (26,826)
Earnings per share - basic and diluted	$ (0.33)
Consolidated Statement of Cash Flows
Net loss	$ (26,826)