CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities
Net income (loss)	$ (21,879)	$ 13,147
Adjustments to reconcile net income (loss) to cash used in operating activities:
Depreciation	737	1,026
Charge for 401(k) company common stock match	356	350
Stock-based compensation	2,441	2,935
Inventory impairment	317
Changes in operating assets and liabilities:
Accounts receivables	338	(508)
Due from related party	(16)	311
Unbilled receivables	101	(363)
Prepaid expenses and other assets	(195)	94
Inventory	(513)	(3,028)
Accounts payable	(811)	(272)
Accrued expenses	(360)	(101)
Other current liabilities	141
Deferred rent and other long-term liabilities	(254)	(115)
Deferred revenue	(617)	(37,900)
Net cash used in operating activities	(20,214)	(24,424)
Cash flows from investing activities
Purchase of property and equipment	(281)	(397)
Proceeds from sale of property and equipment		12
Change in restricted cash	(25)	28
Purchase of investments	(15,621)	(56,428)
Proceeds from the sale and maturity of short-term investments	30,447	77,320
Net cash provided by investing activities	14,520	20,535
Cash flows from financing activities
Proceeds from options exercised	14	19
Net cash provided by financing activities	14	19
Effect of exchange rate changes on cash and cash equivalents	(20)	(2)
Net decrease in cash and cash equivalents	(5,700)	(3,872)
Cash and cash equivalents at beginning of period	14,572	21,277
Cash and cash equivalents at end of period	$ 8,872	$ 17,405