Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 43.2	$ 8.1
Short-term marketable securities, available-for-sale	11.4	40.6
Accounts receivable, net	26.1	19.5
Inventory	9.0	7.4
Prepaid and other current assets	3.4	2.0
Total current assets	93.1	77.6
Property and equipment, net	20.7	18.9
Restricted cash	1.0	1.0
Intangible assets, net	3.6	4.2
Goodwill	3.2	3.2
Other assets	0.9	1.1
Total assets	122.5	106.0
Current liabilities:
Accounts payable and accrued liabilities	14.1	8.7
Accrued payroll and related expenses	15.1	9.2
Secured Debt, Current	2.2	0.2
Current portion of deferred revenue	0.7	1.4
Total current liabilities	32.1	19.5
Other liabilities	1.7	2.1
Secured Long-term Debt, Noncurrent	4.6	6.8
Long-term portion of deferred revenue	0	0.6
Total liabilities	38.4	29.0
Commitments and contingencies (Note 4)
Stockholders' equity:
Preferred stock, $0.001 par value, 5.0 shares authorized; no shares issued and outstanding at December 31, 2013 and December 31, 2012, respectively	0	0
Common stock, $0.001 par value, 100.0 authorized; 72.8 and 72.5 issued and outstanding, respectively, at December 31, 2013; and 69.7 and 69.5 shares issued and outstanding, respectively, at December 31, 2012	0.1	0.1
Additional paid-in capital	559.5	522.6
Accumulated other comprehensive loss	(0.1)	(0.1)
Accumulated deficit	(475.4)	(445.6)
Total stockholders' equity	84.1	77.0
Total liabilities and stockholders' equity	$ 122.5	$ 106.0