Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 129,625	$ 129,294
Restricted cash	658	657
Short-term investments	189,771	115,252
Accounts receivable, net	79,991	45,666
Contract assets	21,246	25,351
Inventories	145,906	133,067
Deferred cost of sales	433	445
Prepaid expenses and other current assets	19,301	14,966
Assets held for sale		11,180
Total current assets	586,931	475,878
Property, plant, and equipment, net	65,271	75,711
Operating lease right-of-use assets	10,275	14,453
Intangible assets, net	46,185	61,518
Goodwill	181,943	181,943
Deferred income taxes	1,440	1,549
Other assets	6,019	7,036
Total assets	898,064	818,088
Current liabilities:
Accounts payable	33,656	21,281
Accrued expenses and other current liabilities	44,876	41,243
Customer deposits and deferred revenue	67,235	54,870
Income taxes payable	914	830
Total current liabilities	146,681	118,224
Deferred income taxes	5,240	5,648
Long-term debt	321,115	300,068
Operating lease long-term liabilities	6,305	10,300
Other liabilities	10,349	9,336
Total liabilities	489,690	443,576
Stockholders' equity:
Preferred stock, $0.01 par value; 500,000 shares authorized; no shares issued and outstanding.
Common stock, $0.01 par value; 120,000,000 shares authorized; 49,723,751 shares issued and outstanding at December 31, 2020 and 48,994,346 shares issued and outstanding at December 31, 2019	497	490
Additional paid-in capital	1,113,352	1,071,058
Accumulated deficit	(707,321)	(698,930)
Accumulated other comprehensive income	1,846	1,894
Total stockholders' equity	408,374	374,512
Total liabilities and stockholders' equity	$ 898,064	$ 818,088