Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (2,356)	$ (5,539)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Stock-based compensation expense	1,978	1,366
Depreciation and amortization	570	678
Other	144	67
Changes in operating assets and liabilities:
Accounts receivable	3,663	(10,799)
Inventories	(1,309)	(2,028)
Contract assets	(1,694)	997
Prepaid expenses and other assets	(154)	(1,364)
Accounts payable	5,479	4,137
Accrued expenses and other liabilities	(1,051)	(25)
Deferred revenue	310	520
Net cash provided by (used in) operating activities	5,580	(11,990)
Cash flows from investing activities:
Purchases of equipment, molds, furniture and fixtures	(641)	(391)
Proceeds from maturities of investment securities	6,000
Net cash provided by (used in) investing activities	5,359	(391)
Cash flows from financing activities:
Proceeds from issuance of common stock, net		7,785
Proceeds from exercise of stock options	271	350
Taxes paid related to net share settlement of equity awards	(597)	(408)
Net cash provided by (used in) financing activities	(326)	7,727
Net increase (decrease) in cash and cash equivalents	10,613	(4,654)
Cash and cash equivalents:
Beginning of period	23,201	27,892
End of period	33,814	23,238
Supplemental disclosure of cash flow information:
Cash paid for interest	935	594
Supplemental disclosure of non-cash investing activities:
Purchases of equipment, molds, furniture and fixtures recorded in accounts payable and accrued expenses	$ 1,131	$ 399