Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:
Net loss	$ (41,303)	$ (30,857)	$ (16,550)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of intangible assets	3,374	3,509	3,716
Depreciation and amortization of property and equipment	6,944	8,908	7,755
Loss on impairment and disposal of property and equipment	1,582	1,551	49
Allowance for bad debt	386	133	(41)
Impairment of marketable securities	0	753	0
Gain from extinguishment of asset retirement obligation	0	(212)	(124)
Stock-based compensation	4,389	5,076	9,431
Common stock issuances for royalty payment to a licensor	0	68	0
Accretion of asset retirement obligation	0	30	39
Accretion of premium on marketable securities	42	697	771
Changes in operating assets and liabilities:
Accounts receivable	1,629	11,372	(3,583)
Inventories	(185)	3,186	(1,671)
Prepaid expenses and other current assets	850	(3,051)	(682)
Other assets	337	(1,330)	513
Accounts payable	308	(6,710)	1,156
Accrued compensation	130	(3,290)	(1,322)
Other accrued liabilities	(2,724)	197	4,351
Deferred revenues	1,629	(1,789)	(4,339)
Net cash used in operating activities	(22,998)	(11,892)	(490)
Investing activities:
Decrease (increase) in restricted cash	800	0	(45)
Purchase of property and equipment	(1,175)	(2,933)	(10,736)
Purchase of marketable securities	0	(20,638)	(52,564)
Proceeds from sale of marketable securities	0	10,397	6,037
Proceeds from maturities of marketable securities	13,409	29,885	8,500
Proceeds from disposal of property and equipment	238	0	0
Net cash provided by (used in) investing activities	13,272	16,711	(48,808)
Financing activities:
Proceeds from exercises of stock options	318	1,257	2,579
Taxes paid related to net share settlement of equity awards	(465)	0	0
Net cash provided by (used in) financing activities	(147)	1,257	2,579
Effect of exchange rate changes on cash and cash equivalents	0	165	85
Net increase (decrease) in cash and cash equivalents	(9,873)	6,241	(46,634)
Cash and cash equivalents at the beginning of the year	32,003	25,762	72,396
Cash and cash equivalents at the end of the year	22,130	32,003	25,762
Supplemental disclosures of cash flow information:
Cash paid for income taxes	103	126	89
Long term deposit in other assets transferred to property and equipment	1,857	0	0
Equipment in property and equipment transferred to assets held for sale	$ 2,179	$ 0	$ 0