CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 24,846	$ 32,695
Short-term marketable securities	26,164	24,127
Accounts receivable, net	16,568	17,329
Inventories	18,355	19,733
Prepaid expenses and other current assets	4,679	3,198
Total current assets	90,612	97,082
Marketable securities	32,998	36,756
Plant and equipment:
Equipment and furniture	201,402	199,908
Leasehold improvements	46,699	46,667
Projects in process	1,800	2,049
	249,901	248,624
Less accumulated depreciation and amortization	198,066	193,900
	51,835	54,724
Other assets	258	239
Total assets	175,703	188,801
Current liabilities:
Accounts payable	12,149	11,905
Accrued liabilities	6,713	7,946
Accrued restructuring costs	377	0
Total current liabilities	19,239	19,851
Other long-term liabilities	2,326	2,425
Commitments and contingencies
Stockholders' equity:
Common stock, $0.01 par value, 144,390 shares authorized, 70,561 issued at March 31, 2012 and 69,394 issued at December 31, 2011	706	694
Additional paid-in capital	605,806	602,757
Accumulated deficit	(454,933)	(439,113)
Accumulated other comprehensive income	2,818	2,446
Treasury stock at cost: 115 shares	(259)	(259)
Total stockholders' equity	154,138	166,525
Total liabilities and stockholders' equity	$ 175,703	$ 188,801