CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 93,761	$ 106,045
Accounts receivable, net of reserve of $313 and $308, respectively (Note 1)	52,563	30,913
Inventories, net of obsolescence reserve of $852 and $851, respectively (Note 1)	1,887	3,311
Prepaid expenses	3,985	3,059
Deferred program expenses	192	5
Other current assets	778	781
Total current assets	153,166	144,114
Property and equipment, including capitalized software development costs, net of accumulated depreciation of $37,948 and $36,891, respectively	23,863	22,397
Operating lease right-of-use assets (Note 10)	1,305	1,464
Goodwill (Note 3)	14,916	14,916
Other assets	990	926
Total assets	194,240	183,817
Current liabilities
Accounts payable and other accrued liabilities (Note 5)	31,765	20,899
Accrued compensation and benefits	7,261	8,474
Contract liabilities (Notes 1 and 5)	6,751	5,654
Finance lease obligations - short-term (Note 10)	1,368	1,339
Operating lease obligations - short term (Note 10)	660	677
Other current liabilities	3,188	1,903
Total current liabilities	50,993	38,946
Finance lease obligations - long-term (Note 10)	13,951	14,301
Operating lease obligations - long-term (Note 10)	788	941
Deferred income taxes (Note 7)	661	652
Other liabilities (Note 7)	1,883	1,873
Total liabilities	68,276	56,713
Commitments and contingencies (Note 8)
Stockholders' equity
Common stock	103	103
Additional paid-in capital	284,470	270,800
Accumulated other comprehensive income	12	44
Accumulated deficit	(158,621)	(143,843)
Total stockholders' equity	125,964	127,104
Total liabilities and stockholders' equity	$ 194,240	$ 183,817