Selected Quarterly Financial Information (unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								9 Months Ended	12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Jun. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Quarterly Financial Data [Abstract]
Revenue	$ 43,091	$ 33,473	$ 42,277	$ 49,306	$ 47,488	$ 41,062	$ 37,780	$ 37,451		$ 168,147	$ 163,781	$ 200,928
Cost of revenue	37,718	29,429	34,444	38,358	42,891	36,677	32,404	33,983		139,949	145,955	158,165
Gross profit	5,373	4,044	7,833	10,948	4,597	4,385	5,376	3,468		28,198	17,826	42,763
Operating expenses (income):
Selling, general, and administrative	6,705	7,039	6,771	6,904	10,258	8,758	8,365	7,480		27,419	34,861	35,582
Research and development	5,796	4,674	4,112	5,390	4,581	4,996	5,781	6,980		19,972	22,338	32,853
Impairment					0	1,425	0	0	1,400	0	1,425	8,000
Litigation settlements, net					0	1,050	0	0		0	1,050	(1,145)
Flood-related loss					0	(293)	114	5,698		0	5,519	0
Flood-related insurance proceeds	0	0	(14,808)	(4,192)	(4,000)	0	0	(5,000)		(19,000)	(9,000)	0
Gain on sale of assets	0	0	(413)	0	51	(2,793)	0	0		(413)	(2,742)	0
Total operating expense	12,501	11,713	(4,338)	8,102	10,890	13,143	14,260	15,158		27,978	53,451	75,290
Operating income (loss)	(7,128)	(7,669)	12,171	2,846	(6,293)	(8,758)	(8,884)	(11,690)		220	(35,625)	(32,527)
Other income (expense):
Interest expense, net	(191)	(185)	(186)	(238)	(281)	(146)	(121)	(129)		(800)	(677)	(640)
Foreign exchange gain (loss)	95	181	(21)	101	(15)	(196)	167	89		356	45	735
Gain on sale of equity method investment	4,800	0	0	0						4,800	0	0
Loss from equity method investment					0	0	(241)	(960)		0	(1,201)	(1,842)
Change in fair value of financial instruments	172	373	(267)	237	21	61	(256)	105		515	(69)	70
Other income (expense)	0	17	0	0	0	0	0	0		17	0	(15)
Total other income (expense)	4,876	386	(474)	100	(275)	(281)	(451)	(895)		4,888	(1,902)	(1,692)
Income (loss) before income tax expense	(2,252)	(7,283)	11,697	2,946	(6,568)	(9,039)	(9,335)	(12,585)		5,108	(37,527)	(34,219)
Income tax expense	0	0	0	(120)		0	0	(1,644)		(120)	(1,644)	0
Net income (loss)	$ (2,252)	$ (7,283)	$ 11,697	$ 2,826	$ (6,568)	$ (9,039)	$ (9,335)	$ (14,229)		$ 4,988	$ (39,171)	$ (34,219)
Per share data:
Net income (loss) per basic share (in dollars per share)	$ (0.08)	$ (0.27)	$ 0.44	$ 0.11						$ 0.19	$ (1.66)	$ (1.54)
Net income (loss) per diluted share (in dollars per share)	$ (0.08)	$ (0.27)	$ 0.44	$ 0.11						$ 0.19	$ (1.66)	$ (1.54)
Weighted-average number of basic shares outstanding	27,158	26,609	26,310	25,977						26,531	23,559	22,228
Weighted-average number of diluted shares outstanding	27,158	26,609	26,642	26,236						26,812	23,559	22,228
Net loss per basic and diluted share (in dollars per share)					$ (0.27)	$ (0.38)	$ (0.40)	$ (0.61)
Weighted-average number of basic and diluted shares outstanding					23,892	23,686	23,529	23,476