Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash and cash equivalents	$ 33,949	$ 34,346
Short-term investments	49,064	42,408
Accounts receivable, net of allowance for doubtful accounts of $21 and $61 as of September 30, 2017 and December 31, 2016, respectively	17,186	26,190
Inventories	13,206	12,629
Prepaid expenses and other current assets	7,864	6,289
Total current assets	121,269	121,862
Property and equipment, net	7,005	9,008
Goodwill	513	513
Other assets	5,362	5,100
Total assets	134,149	136,483
CURRENT LIABILITIES:
Accounts payable	9,709	10,762
Accrued liabilities	8,976	9,300
Debt, current	0	20,000
Deferred revenue, current	36,761	31,727
Total current liabilities	55,446	71,789
Debt, non-current	20,000	0
Deferred revenue, non-current	35,732	34,177
Other liabilities	1,791	1,829
Total liabilities	112,969	107,795
Commitments and contingencies (Note 5)
Stockholders’ equity:
Preferred stock, par value of $0.001 per share - 25,000,000 shares authorized as of September 30, 2017 and December 31, 2016; no shares issued and outstanding as of September 30, 2017 and December 31, 2016	0	0
Common stock, par value of $0.001 per share - 500,000,000 shares authorized as of September 30, 2017 and December 31, 2016; 53,598,569 and 52,245,252 shares issued and outstanding as of September 30, 2017 and December 31, 2016, respectively	55	52
Additional paid–in capital	273,287	258,063
Treasury stock - 1,161,243 and 364,627 shares as of September 30, 2017 and December 31, 2016, respectively	(5,169)	(2,139)
Accumulated other comprehensive loss	(9)	(31)
Accumulated deficit	(246,984)	(227,257)
Total stockholders’ equity	21,180	28,688
Total liabilities and stockholders’ equity	$ 134,149	$ 136,483

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).

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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.