Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 100,426	$ 104,339
Accounts receivable, net	15,889	14,107
Inventory	39,213	34,950
Prepaid expenses and other current assets	2,475	2,084
Total current assets	158,003	155,480
Property and equipment, net	12,540	8,290
Field equipment, net	13,036	13,660
Deferred cost of revenues	40,458	40,081
Intangible assets, net	24,013	25,412
Goodwill	42,698	42,698
Other assets	675	473
Total assets	291,423	286,094
Current liabilities:
Accounts payable	22,620	16,811
Accrued expenses	14,201	19,537
Current portion of long-term debt	16	43
Total current liabilities	36,837	36,391
Deferred revenues	55,995	55,366
Long-term debt	41,818	40,454
Other long-term liabilities	5,639	1,754
Total liabilities	140,289	133,965
Commitments and contingencies (Note 10)
Stockholders' equity:
Undesignated preferred stock: par value $0.001, 5,000,000 shares authorized; no shares issued and outstanding as of June 30, 2011 and December 31, 2010	0	0
Common stock: par value $0.001, 100,000,000 shares authorized; 55,172,136 and 54,043,317 shares issued as of June 30, 2011 and December 31, 2010, respectively	55	53
Additional paid-in capital	479,186	465,642
Accumulated deficit	(319,986)	(308,426)
Accumulated other comprehensive income	395	85
Treasury stock, at cost: 480,923 and 325,104 shares as of June 30, 2011 and December 31, 2010, respectively	(8,516)	(5,225)
Total stockholders' equity	151,134	152,129
Total liabilities and stockholders' equity	$ 291,423	$ 286,094