Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 16,598	$ 26,487
Accounts receivable, net of allowances of $421 at June 30, 2015 and $428 at December 31, 2014	2,794	3,870
Inventories	968	1,395
Prepaid expenses and other current assets	1,034	1,255
Total current assets	21,394	33,007
Restricted cash	786	711
Marketable securities	1,942	688
Property and equipment, net	3,155	3,995
Intangible assets, net	4,499	6,186
Goodwill	3,241	3,241
Other non-current assets	275	294
Total assets	35,292	48,122
Current liabilities:
Accounts payable	1,708	4,673
Accrued compensation	2,615	2,946
Other accrued liabilities	1,871	2,619
Deferred revenue	5,166	3,497
Total current liabilities	11,360	13,735
Deferred revenue, net of current portion	2,804	3,813
Other long-term liabilities	$ 4,027	$ 4,263
Commitments and contingencies (Note 11)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 5,000 shares authorized, none issued and outstanding	$ 0	$ 0
Common stock, $0.0001 par value; 100,000 shares authorized at June 30, 2015 and December 31, 2014; shares issued and outstanding of 40,254 at June 30, 2015 and 39,563 at December 31, 2014	4	4
Additional paid-in capital	303,299	302,379
Accumulated other comprehensive income loss	650	(142)
Accumulated deficit	(286,852)	(275,930)
Total stockholders’ equity	17,101	26,311
Total liabilities and stockholders’ equity	$ 35,292	$ 48,122

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.