Quarterly Results of Operations (Unaudited) - Quarterly Consolidated Statement of Operations Data (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	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
Segment Reporting Information [Line Items]
Revenues	$ 6,896	$ 11,863	$ 7,030	$ 9,224	$ 9,293	$ 26,306	$ 7,864	$ 13,623	$ 35,013	$ 57,086	$ 63,393
Gross profit	6,857	11,802	6,976	9,181	9,235	26,255	7,805	13,600
Operating income (loss)	(12,216)	(5,443)	(14,911)	(12,852)	(11,208)	10,114	(9,561)	(4,608)	(45,422)	(15,263)	4,719
Income (loss) from continuing operations before provisions for income taxes	(12,109)	(5,243)	(14,746)	(12,713)	(11,363)	10,778	(9,528)	(4,396)	(44,811)	(14,509)	4,449
Benefit (provision) for income taxes	(185)	(44)	(99)	(152)	(26,785)	(3,760)	(3,323)	(1,701)	(480)	(25,521)	(1,591)
Income (loss) from continuing operations	(12,294)	(5,287)	(14,845)	(12,865)	(38,148)	7,018	(6,205)	(2,695)	(45,291)	(40,030)	2,858
Income from discontinued operations, net of tax	0	0	0	0	0	0	649	0	0	649	0
Net income (loss)	$ (12,294)	$ (5,287)	$ (14,845)	$ (12,865)	$ (38,148)	$ 7,018	$ (5,556)	$ (2,695)	$ (45,291)	$ (39,381)	$ 2,858
Basic net income (loss) per share - Continuing operations (in dollars per share)	$ (0.42)	$ (0.18)	$ (0.51)	$ (0.44)	$ (1.32)	$ 0.24	$ (0.22)	$ (0.09)	$ (1.55)	$ (1.39)	$ 0.10
Basic net income (loss) per share - Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00	0.00	0.00	0.02	0.00	0.00	0.02	0.00
Basic net income (loss) per share (in dollars per share)	$ (0.42)	$ (0.18)	$ (0.51)	$ (0.44)	$ (1.32)	$ 0.24	$ (0.20)	$ (0.09)	$ (1.55)	$ (1.37)	$ 0.10
Shares used in calculating basic net income (loss) per share (in shares)	29,250	29,245	29,193	29,024	28,860	28,849	28,834	28,493	29,179	28,759	28,097
Diluted net income (loss) per share - Continuing operations (in dollars per share)	$ (0.42)	$ (0.18)	$ (0.51)	$ (0.44)	$ (1.32)	$ 0.24	$ (0.22)	$ (0.09)	$ (1.55)	$ (1.39)	$ 0.10
Diluted net income (loss) per share - Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00	0.00	0.00	0.02	0.00	0.00	0.02	0.00
Diluted net income (loss) per share (in dollars per shares)	$ (0.42)	$ (0.18)	$ (0.51)	$ (0.44)	$ (1.32)	$ 0.24	$ (0.20)	$ (0.09)	$ (1.55)	$ (1.37)	$ 0.10
Shares used in computation of diluted net income (loss) per share (in shares)	29,250	29,245	29,193	29,024	28,860	29,298	28,834	28,493	29,179	28,759	29,015
Samsung Electronics
Segment Reporting Information [Line Items]
Revenues		$ 19,000