Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 78,916	$ 57,389
Accounts receivable	26,171	20,326
Inventory	30,441	19,375
Deposits on purchased inventory	10,001	7,043
Deferred cost of revenue	4,110	13,696
Prepaid expenses and other current assets	4,374	4,862
Total current assets	154,013	122,691
Property and equipment, net	12,955	11,564
Restricted cash	1,143	1,143
Intangible assets, net	73	78
Other assets	441	235
TOTAL ASSETS	168,625	135,711
Current liabilities:
Accounts payable	13,443	11,014
Accrued liabilities	7,897	7,207
Customer deposits	9,620	17,820
Deferred revenue, current portion	9,670	20,151
Total current liabilities	40,630	56,192
Deferred revenue, net of current portion	3,343	3,238
Long-term debt	44,551	44,504
Warrant liabilities	14,238	22,420
Other long-term liabilities	8,199	7,370
TOTAL LIABILITIES	110,961	133,724
Commitments and contingencies (Note 6)
Stockholders’ equity:
Convertible preferred stock, par value of $0.01 per share; 10,000,000 shares authorized at March 31, 2018 and December 31, 2017; 3,000,581 shares issued and outstanding at March 31, 2018 and no shares issued and outstanding at December 31, 2017	30
Common stock, par value of $0.01 per share; 300,000,000 shares authorized at March 31, 2018 and December 31, 2017; 72,022,089 and 67,653,974 shares issued and outstanding at March 31, 2018 and December 31, 2017	710	666
Additional paid-in capital	384,319	321,174
Accumulated deficit	(327,395)	(319,853)
TOTAL STOCKHOLDERS’ EQUITY	57,664	1,987
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 168,625	$ 135,711

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.